Merge branch 'master' into testing

70 files changed, 2497 insertions, 1418 deletions

diff --git a/ext/bg/background.html b/ext/bg/background.html
index af87eddb..7fd1c477 100644
--- a/ext/bg/background.html
+++ b/ext/bg/background.html
@@ -26,20 +26,20 @@
         <script src="/bg/js/mecab.js"></script>
         <script src="/bg/js/audio.js"></script>
         <script src="/bg/js/backend-api-forwarder.js"></script>
+        <script src="/bg/js/clipboard-monitor.js"></script>
         <script src="/bg/js/conditions.js"></script>
         <script src="/bg/js/database.js"></script>
         <script src="/bg/js/deinflector.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/bg/js/json-schema.js"></script>
         <script src="/bg/js/options.js"></script>
         <script src="/bg/js/profile-conditions.js"></script>
         <script src="/bg/js/request.js"></script>
-        <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/translator.js"></script>
         <script src="/bg/js/util.js"></script>
         <script src="/mixed/js/audio.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
 
         <script src="/bg/js/backend.js"></script>
     </body>
diff --git a/ext/bg/css/settings.css b/ext/bg/css/settings.css
index 815a88fa..d686e8f8 100644
--- a/ext/bg/css/settings.css
+++ b/ext/bg/css/settings.css
@@ -222,6 +222,20 @@ html:root[data-operating-system=openbsd] [data-show-for-operating-system~=openbs
     display: initial;
 }
 
+html:root[data-browser=edge] [data-hide-for-browser~=edge],
+html:root[data-browser=chrome] [data-hide-for-browser~=chrome],
+html:root[data-browser=firefox] [data-hide-for-browser~=firefox],
+html:root[data-browser=firefox-mobile] [data-hide-for-browser~=firefox-mobile],
+html:root[data-operating-system=mac] [data-hide-for-operating-system~=mac],
+html:root[data-operating-system=win] [data-hide-for-operating-system~=win],
+html:root[data-operating-system=android] [data-hide-for-operating-system~=android],
+html:root[data-operating-system=cros] [data-hide-for-operating-system~=cros],
+html:root[data-operating-system=linux] [data-hide-for-operating-system~=linux],
+html:root[data-operating-system=openbsd] [data-hide-for-operating-system~=openbsd] {
+    display: none;
+}
+
+
 @media screen and (max-width: 740px) {
     .col-xs-6 {
         float: none;
diff --git a/ext/bg/data/dictionary-index-schema.json b/ext/bg/data/dictionary-index-schema.json
new file mode 100644
index 00000000..9311f14c
--- /dev/null
+++ b/ext/bg/data/dictionary-index-schema.json
@@ -0,0 +1,69 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "object",
+    "description": "Index file containing information about the data contained in the dictionary.",
+    "required": [
+        "title",
+        "revision"
+    ],
+    "properties": {
+        "title": {
+            "type": "string",
+            "description": "Title of the dictionary."
+        },
+        "revision": {
+            "type": "string",
+            "description": "Revision of the dictionary. This value is only used for displaying information."
+        },
+        "sequenced": {
+            "type": "boolean",
+            "default": false,
+            "description": "Whether or not this dictionary can be used as the primary dictionary. Primary dictionaries typically contain term/expression definitions."
+        },
+        "format": {
+            "type": "integer",
+            "description": "Format of data found in the JSON data files.",
+            "enum": [1, 2, 3]
+        },
+        "version": {
+            "type": "integer",
+            "description": "Alias for format.",
+            "enum": [1, 2, 3]
+        },
+        "tagMeta": {
+            "type": "object",
+            "description": "Tag information for terms and kanji. This object is obsolete and individual tag files should be used instead.",
+            "additionalProperties": {
+                "type": "object",
+                "description": "Information about a single tag. The object key is the name of the tag.",
+                "properties": {
+                    "category": {
+                        "type": "string",
+                        "description": "Category for the tag."
+                    },
+                    "order": {
+                        "type": "number",
+                        "description": "Sorting order for the tag."
+                    },
+                    "notes": {
+                        "type": "string",
+                        "description": "Notes for the tag."
+                    },
+                    "score": {
+                        "type": "number",
+                        "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+                    }
+                },
+                "additionalProperties": false
+            }
+        }
+    },
+    "anyOf": [
+        {
+            "required": ["format"]
+        },
+        {
+            "required": ["version"]
+        }
+    ]
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-bank-v1-schema.json b/ext/bg/data/dictionary-kanji-bank-v1-schema.json
new file mode 100644
index 00000000..6dad5a7a
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-bank-v1-schema.json
@@ -0,0 +1,33 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing kanji information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single kanji character.",
+        "minItems": 4,
+        "items": [
+            {
+                "type": "string",
+                "description": "Kanji character.",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated onyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated kunyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the kanji character. An empty string is treated as no tags."
+            }
+        ],
+        "additionalItems": {
+            "type": "string",
+            "description": "A meaning for the kanji character."
+        }
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-bank-v3-schema.json b/ext/bg/data/dictionary-kanji-bank-v3-schema.json
new file mode 100644
index 00000000..a5b82039
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-bank-v3-schema.json
@@ -0,0 +1,44 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing kanji information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single kanji character.",
+        "minItems": 6,
+        "items": [
+            {
+                "type": "string",
+                "description": "Kanji character.",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated onyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated kunyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the kanji character. An empty string is treated as no tags."
+            },
+            {
+                "type": "array",
+                "description": "Array of meanings for the kanji character.",
+                "items": {
+                    "type": "string",
+                    "description": "A meaning for the kanji character."
+                }
+            },
+            {
+                "type": "object",
+                "description": "Various stats for the kanji character.",
+                "additionalProperties": {
+                    "type": "string"
+                }
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json b/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json
new file mode 100644
index 00000000..62479026
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json
@@ -0,0 +1,25 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Custom metadata for kanji characters.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Metadata about a single kanji character.",
+        "minItems": 3,
+        "items": [
+            {
+                "type": "string",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "enum": ["freq"],
+                "description": "Type of data. \"freq\" corresponds to frequency information."
+            },
+            {
+                "type": ["string", "number"],
+                "description": "Data for the character."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-tag-bank-v3-schema.json b/ext/bg/data/dictionary-tag-bank-v3-schema.json
new file mode 100644
index 00000000..ee5ca64d
--- /dev/null
+++ b/ext/bg/data/dictionary-tag-bank-v3-schema.json
@@ -0,0 +1,32 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing tag information for terms and kanji.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single tag.",
+        "minItems": 5,
+        "items": [
+            {
+                "type": "string",
+                "description": "Tag name."
+            },
+            {
+                "type": "string",
+                "description": "Category for the tag."
+            },
+            {
+                "type": "number",
+                "description": "Sorting order for the tag."
+            },
+            {
+                "type": "string",
+                "description": "Notes for the tag."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-bank-v1-schema.json b/ext/bg/data/dictionary-term-bank-v1-schema.json
new file mode 100644
index 00000000..6ffb26e6
--- /dev/null
+++ b/ext/bg/data/dictionary-term-bank-v1-schema.json
@@ -0,0 +1,36 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing term and expression information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single term/expression.",
+        "minItems": 5,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "description": "Reading of the term/expression, or an empty string if the reading is the same as the term/expression."
+            },
+            {
+                "type": ["string", "null"],
+                "description": "String of space-separated tags for the definition. An empty string is treated as no tags."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated rule identifiers for the definition which is used to validate delinflection. Valid rule identifiers are: v1: ichidan verb; v5: godan verb; vs: suru verb; vk: kuru verb; adj-i: i-adjective. An empty string corresponds to words which aren't inflected, such as nouns."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            }
+        ],
+        "additionalItems": {
+            "type": "string",
+            "description": "Single definition for the term/expression."
+        }
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-bank-v3-schema.json b/ext/bg/data/dictionary-term-bank-v3-schema.json
new file mode 100644
index 00000000..bb982e36
--- /dev/null
+++ b/ext/bg/data/dictionary-term-bank-v3-schema.json
@@ -0,0 +1,48 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing term and expression information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single term/expression.",
+        "minItems": 8,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "description": "Reading of the term/expression, or an empty string if the reading is the same as the term/expression."
+            },
+            {
+                "type": ["string", "null"],
+                "description": "String of space-separated tags for the definition. An empty string is treated as no tags."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated rule identifiers for the definition which is used to validate delinflection. Valid rule identifiers are: v1: ichidan verb; v5: godan verb; vs: suru verb; vk: kuru verb; adj-i: i-adjective. An empty string corresponds to words which aren't inflected, such as nouns."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            },
+            {
+                "type": "array",
+                "description": "Array of definitions for the term/expression.",
+                "items": {
+                    "type": "string",
+                    "description": "Single definition for the term/expression."
+                }
+            },
+            {
+                "type": "integer",
+                "description": "Sequence number for the term/expression. Terms/expressions with the same sequence number can be shown together when the \"resultOutputMode\" option is set to \"merge\"."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the term/expression. An empty string is treated as no tags."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-meta-bank-v3-schema.json b/ext/bg/data/dictionary-term-meta-bank-v3-schema.json
new file mode 100644
index 00000000..1cc0557f
--- /dev/null
+++ b/ext/bg/data/dictionary-term-meta-bank-v3-schema.json
@@ -0,0 +1,25 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Custom metadata for terms/expressions.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Metadata about a single term/expression.",
+        "minItems": 3,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "enum": ["freq"],
+                "description": "Type of data. \"freq\" corresponds to frequency information."
+            },
+            {
+                "type": ["string", "number"],
+                "description": "Data for the term/expression."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/options-schema.json b/ext/bg/data/options-schema.json
index a20a0619..d6207952 100644
--- a/ext/bg/data/options-schema.json
+++ b/ext/bg/data/options-schema.json
@@ -79,6 +79,7 @@
                                 "type": "object",
                                 "required": [
                                     "enable",
+                                    "enableClipboardPopups",
                                     "resultOutputMode",
                                     "debugInfo",
                                     "maxResults",
@@ -111,6 +112,10 @@
                                         "type": "boolean",
                                         "default": true
                                     },
+                                    "enableClipboardPopups": {
+                                        "type": "boolean",
+                                        "default": false
+                                    },
                                     "resultOutputMode": {
                                         "type": "string",
                                         "enum": ["group", "merge", "split"],
@@ -290,7 +295,8 @@
                                     "popupNestingMaxDepth",
                                     "enablePopupSearch",
                                     "enableOnPopupExpressions",
-                                    "enableOnSearchPage"
+                                    "enableOnSearchPage",
+                                    "enableSearchTags"
                                 ],
                                 "properties": {
                                     "middleMouse": {
@@ -348,6 +354,10 @@
                                     "enableOnSearchPage": {
                                         "type": "boolean",
                                         "default": true
+                                    },
+                                    "enableSearchTags": {
+                                        "type": "boolean",
+                                        "default": false
                                     }
                                 }
                             },
diff --git a/ext/bg/js/anki.js b/ext/bg/js/anki.js
index 10a07061..39c6ad51 100644
--- a/ext/bg/js/anki.js
+++ b/ext/bg/js/anki.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global requestJson*/
 
 /*
  * AnkiConnect
diff --git a/ext/bg/js/api.js b/ext/bg/js/api.js
index 285b8016..0c244ffa 100644
--- a/ext/bg/js/api.js
+++ b/ext/bg/js/api.js
@@ -17,16 +17,16 @@
  */
 
 
-function apiTemplateRender(template, data, dynamic) {
-    return _apiInvoke('templateRender', {data, template, dynamic});
+function apiTemplateRender(template, data) {
+    return _apiInvoke('templateRender', {data, template});
 }
 
 function apiAudioGetUrl(definition, source, optionsContext) {
     return _apiInvoke('audioGetUrl', {definition, source, optionsContext});
 }
 
-function apiGetDisplayTemplatesHtml() {
-    return _apiInvoke('getDisplayTemplatesHtml');
+function apiClipboardGet() {
+    return _apiInvoke('clipboardGet');
 }
 
 function _apiInvoke(action, params={}) {
diff --git a/ext/bg/js/audio.js b/ext/bg/js/audio.js
index 36ac413b..d300570b 100644
--- a/ext/bg/js/audio.js
+++ b/ext/bg/js/audio.js
@@ -16,13 +16,14 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global jpIsStringEntirelyKana, audioGetFromSources*/
 
 const audioUrlBuilders = new Map([
     ['jpod101', async (definition) => {
         let kana = definition.reading;
         let kanji = definition.expression;
 
-        if (!kana && wanakana.isHiragana(kanji)) {
+        if (!kana && jpIsStringEntirelyKana(kanji)) {
             kana = kanji;
             kanji = null;
         }
@@ -51,7 +52,7 @@ const audioUrlBuilders = new Map([
         for (const row of dom.getElementsByClassName('dc-result-row')) {
             try {
                 const url = row.querySelector('audio>source[src]').getAttribute('src');
-                const reading = row.getElementsByClassName('dc-vocab_kana').item(0).innerText;
+                const reading = row.getElementsByClassName('dc-vocab_kana').item(0).textContent;
                 if (url && reading && (!definition.reading || definition.reading === reading)) {
                     return audioUrlNormalize(url, 'https://www.japanesepod101.com', '/learningcenter/reference/');
                 }
@@ -167,10 +168,8 @@ async function audioInject(definition, fields, sources, optionsContext) {
     }
 
     try {
-        let audioSourceDefinition = definition;
-        if (hasOwn(definition, 'expressions')) {
-            audioSourceDefinition = definition.expressions[0];
-        }
+        const expressions = definition.expressions;
+        const audioSourceDefinition = Array.isArray(expressions) ? expressions[0] : definition;
 
         const {url} = await audioGetFromSources(audioSourceDefinition, sources, optionsContext, true);
         if (url !== null) {
diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index eeab68a5..e3bf7bda 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -16,12 +16,21 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global optionsSave, utilIsolate
+conditionsTestValue, profileConditionsDescriptor, profileOptionsGetDefaultFieldTemplates
+handlebarsRenderDynamic
+requestText, requestJson, optionsLoad
+dictConfigured, dictTermsSort, dictEnabledSet, dictNoteFormat
+audioGetUrl, audioInject
+jpConvertReading, jpDistributeFuriganaInflected, jpKatakanaToHiragana
+Translator, AnkiConnect, AnkiNull, Mecab, BackendApiForwarder, JsonSchema, ClipboardMonitor*/
 
 class Backend {
     constructor() {
         this.translator = new Translator();
         this.anki = new AnkiNull();
         this.mecab = new Mecab();
+        this.clipboardMonitor = new ClipboardMonitor();
         this.options = null;
         this.optionsSchema = null;
         this.optionsContext = {
@@ -34,7 +43,11 @@ class Backend {
 
         this.clipboardPasteTarget = document.querySelector('#clipboard-paste-target');
 
+        this.popupWindow = null;
+
         this.apiForwarder = new BackendApiForwarder();
+
+        this.messageToken = yomichan.generateId(16);
     }
 
     async prepare() {
@@ -67,6 +80,8 @@ class Backend {
         this.isPreparedResolve();
         this.isPreparedResolve = null;
         this.isPreparedPromise = null;
+
+        this.clipboardMonitor.onClipboardText = (text) => this._onClipboardText(text);
     }
 
     onOptionsUpdated(source) {
@@ -75,7 +90,7 @@ class Backend {
         const callback = () => this.checkLastError(chrome.runtime.lastError);
         chrome.tabs.query({}, (tabs) => {
             for (const tab of tabs) {
-                chrome.tabs.sendMessage(tab.id, {action: 'optionsUpdate', params: {source}}, callback);
+                chrome.tabs.sendMessage(tab.id, {action: 'optionsUpdated', params: {source}}, callback);
             }
         });
     }
@@ -97,6 +112,10 @@ class Backend {
         }
     }
 
+    _onClipboardText(text) {
+        this._onCommandSearch({mode: 'popup', query: text});
+    }
+
     _onZoomChange({tabId, oldZoomFactor, newZoomFactor}) {
         const callback = () => this.checkLastError(chrome.runtime.lastError);
         chrome.tabs.sendMessage(tabId, {action: 'zoomChanged', params: {oldZoomFactor, newZoomFactor}}, callback);
@@ -121,6 +140,12 @@ class Backend {
         } else {
             this.mecab.stopListener();
         }
+
+        if (options.general.enableClipboardPopups) {
+            this.clipboardMonitor.start();
+        } else {
+            this.clipboardMonitor.stop();
+        }
     }
 
     async getOptionsSchema() {
@@ -249,18 +274,18 @@ class Backend {
                 const node = nodes.pop();
                 for (const key of Object.keys(node.obj)) {
                     const path = node.path.concat(key);
-                    const obj = node.obj[key];
-                    if (obj !== null && typeof obj === 'object') {
-                        nodes.unshift({obj, path});
+                    const obj2 = node.obj[key];
+                    if (obj2 !== null && typeof obj2 === 'object') {
+                        nodes.unshift({obj: obj2, path});
                     } else {
-                        valuePaths.push([obj, path]);
+                        valuePaths.push([obj2, path]);
                     }
                 }
             }
             return valuePaths;
         }
 
-        function modifyOption(path, value, options) {
+        function modifyOption(path, value) {
             let pivot = options;
             for (const key of path.slice(0, -1)) {
                 if (!hasOwn(pivot, key)) {
@@ -273,7 +298,7 @@ class Backend {
         }
 
         for (const [value, path] of getValuePaths(changedOptions)) {
-            modifyOption(path, value, options);
+            modifyOption(path, value);
         }
 
         await this._onApiOptionsSave({source});
@@ -294,7 +319,8 @@ class Backend {
 
     async _onApiTermsFind({text, details, optionsContext}) {
         const options = await this.getOptions(optionsContext);
-        const [definitions, length] = await this.translator.findTerms(text, details, options);
+        const mode = options.general.resultOutputMode;
+        const [definitions, length] = await this.translator.findTerms(mode, text, details, options);
         definitions.splice(options.general.maxResults);
         return {length, definitions};
     }
@@ -304,9 +330,9 @@ class Backend {
         const results = [];
         while (text.length > 0) {
             const term = [];
-            const [definitions, sourceLength] = await this.translator.findTermsInternal(
+            const [definitions, sourceLength] = await this.translator.findTerms(
+                'simple',
                 text.substring(0, options.scanning.length),
-                dictEnabledSet(options),
                 {},
                 options
             );
@@ -314,9 +340,9 @@ class Backend {
                 dictTermsSort(definitions);
                 const {expression, reading} = definitions[0];
                 const source = text.substring(0, sourceLength);
-                for (const {text, furigana} of jpDistributeFuriganaInflected(expression, reading, source)) {
-                    const reading = jpConvertReading(text, furigana, options.parsing.readingMode);
-                    term.push({text, reading});
+                for (const {text: text2, furigana} of jpDistributeFuriganaInflected(expression, reading, source)) {
+                    const reading2 = jpConvertReading(text2, furigana, options.parsing.readingMode);
+                    term.push({text: text2, reading: reading2});
                 }
                 text = text.substring(source.length);
             } else {
@@ -339,17 +365,17 @@ class Backend {
                 for (const {expression, reading, source} of parsedLine) {
                     const term = [];
                     if (expression !== null && reading !== null) {
-                        for (const {text, furigana} of jpDistributeFuriganaInflected(
+                        for (const {text: text2, furigana} of jpDistributeFuriganaInflected(
                             expression,
                             jpKatakanaToHiragana(reading),
                             source
                         )) {
-                            const reading = jpConvertReading(text, furigana, options.parsing.readingMode);
-                            term.push({text, reading});
+                            const reading2 = jpConvertReading(text2, furigana, options.parsing.readingMode);
+                            term.push({text: text2, reading: reading2});
                         }
                     } else {
-                        const reading = jpConvertReading(source, null, options.parsing.readingMode);
-                        term.push({text: source, reading});
+                        const reading2 = jpConvertReading(source, null, options.parsing.readingMode);
+                        term.push({text: source, reading: reading2});
                     }
                     result.push(term);
                 }
@@ -436,12 +462,8 @@ class Backend {
         return this.anki.guiBrowse(`nid:${noteId}`);
     }
 
-    async _onApiTemplateRender({template, data, dynamic}) {
-        return (
-            dynamic ?
-            handlebarsRenderDynamic(template, data) :
-            handlebarsRenderStatic(template, data)
-        );
+    async _onApiTemplateRender({template, data}) {
+        return handlebarsRenderDynamic(template, data);
     }
 
     async _onApiCommandExec({command, params}) {
@@ -480,19 +502,30 @@ class Backend {
         return Promise.resolve({frameId});
     }
 
-    _onApiInjectStylesheet({css}, sender) {
+    _onApiInjectStylesheet({type, value}, sender) {
         if (!sender.tab) {
             return Promise.reject(new Error('Invalid tab'));
         }
 
         const tabId = sender.tab.id;
         const frameId = sender.frameId;
-        const details = {
-            code: css,
-            runAt: 'document_start',
-            cssOrigin: 'user',
-            allFrames: false
-        };
+        const details = (
+            type === 'file' ?
+            {
+                file: value,
+                runAt: 'document_start',
+                cssOrigin: 'author',
+                allFrames: false,
+                matchAboutBlank: true
+            } :
+            {
+                code: value,
+                runAt: 'document_start',
+                cssOrigin: 'user',
+                allFrames: false,
+                matchAboutBlank: true
+            }
+        );
         if (typeof frameId === 'number') {
             details.frameId = frameId;
         }
@@ -521,13 +554,30 @@ class Backend {
     }
 
     async _onApiClipboardGet() {
-        const clipboardPasteTarget = this.clipboardPasteTarget;
-        clipboardPasteTarget.value = '';
-        clipboardPasteTarget.focus();
-        document.execCommand('paste');
-        const result = clipboardPasteTarget.value;
-        clipboardPasteTarget.value = '';
-        return result;
+        /*
+        Notes:
+            document.execCommand('paste') doesn't work on Firefox.
+            This may be a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985
+            Therefore, navigator.clipboard.readText() is used on Firefox.
+
+            navigator.clipboard.readText() can't be used in Chrome for two reasons:
+            * Requires page to be focused, else it rejects with an exception.
+            * When the page is focused, Chrome will request clipboard permission, despite already
+              being an extension with clipboard permissions. It effectively asks for the
+              non-extension permission for clipboard access.
+        */
+        const browser = await Backend._getBrowser();
+        if (browser === 'firefox' || browser === 'firefox-mobile') {
+            return await navigator.clipboard.readText();
+        } else {
+            const clipboardPasteTarget = this.clipboardPasteTarget;
+            clipboardPasteTarget.value = '';
+            clipboardPasteTarget.focus();
+            document.execCommand('paste');
+            const result = clipboardPasteTarget.value;
+            clipboardPasteTarget.value = '';
+            return result;
+        }
     }
 
     async _onApiGetDisplayTemplatesHtml() {
@@ -535,6 +585,11 @@ class Backend {
         return await requestText(url, 'GET');
     }
 
+    async _onApiGetQueryParserTemplatesHtml() {
+        const url = chrome.runtime.getURL('/bg/query-parser-templates.html');
+        return await requestText(url, 'GET');
+    }
+
     _onApiGetZoom(params, sender) {
         if (!sender || !sender.tab) {
             return Promise.reject(new Error('Invalid tab'));
@@ -562,26 +617,75 @@ class Backend {
         });
     }
 
+    async _onApiGetMessageToken() {
+        return this.messageToken;
+    }
+
     // Command handlers
 
     async _onCommandSearch(params) {
-        const url = chrome.runtime.getURL('/bg/search.html');
-        if (!(params && params.newTab)) {
-            try {
-                const tab = await Backend._findTab(1000, (url2) => (
-                    url2 !== null &&
-                    url2.startsWith(url) &&
-                    (url2.length === url.length || url2[url.length] === '?' || url2[url.length] === '#')
-                ));
-                if (tab !== null) {
-                    await Backend._focusTab(tab);
-                    return;
+        const {mode='existingOrNewTab', query} = params || {};
+
+        const options = await this.getOptions(this.optionsContext);
+        const {popupWidth, popupHeight} = options.general;
+
+        const baseUrl = chrome.runtime.getURL('/bg/search.html');
+        const queryParams = {mode};
+        if (query && query.length > 0) { queryParams.query = query; }
+        const queryString = new URLSearchParams(queryParams).toString();
+        const url = `${baseUrl}?${queryString}`;
+
+        const isTabMatch = (url2) => {
+            if (url2 === null || !url2.startsWith(baseUrl)) { return false; }
+            const {baseUrl: baseUrl2, queryParams: queryParams2} = parseUrl(url2);
+            return baseUrl2 === baseUrl && (queryParams2.mode === mode || (!queryParams2.mode && mode === 'existingOrNewTab'));
+        };
+
+        const openInTab = async () => {
+            const tab = await Backend._findTab(1000, isTabMatch);
+            if (tab !== null) {
+                await Backend._focusTab(tab);
+                if (queryParams.query) {
+                    await new Promise((resolve) => chrome.tabs.sendMessage(
+                        tab.id, {action: 'searchQueryUpdate', params: {query: queryParams.query}}, resolve
+                    ));
                 }
-            } catch (e) {
-                // NOP
+                return true;
             }
+        };
+
+        switch (mode) {
+            case 'existingOrNewTab':
+                try {
+                    if (await openInTab()) { return; }
+                } catch (e) {
+                    // NOP
+                }
+                chrome.tabs.create({url});
+                return;
+            case 'newTab':
+                chrome.tabs.create({url});
+                return;
+            case 'popup':
+                try {
+                    // chrome.windows not supported (e.g. on Firefox mobile)
+                    if (!isObject(chrome.windows)) { return; }
+                    if (await openInTab()) { return; }
+                    // if the previous popup is open in an invalid state, close it
+                    if (this.popupWindow !== null) {
+                        const callback = () => this.checkLastError(chrome.runtime.lastError);
+                        chrome.windows.remove(this.popupWindow.id, callback);
+                    }
+                    // open new popup
+                    this.popupWindow = await new Promise((resolve) => chrome.windows.create(
+                        {url, width: popupWidth, height: popupHeight, type: 'popup'},
+                        resolve
+                    ));
+                } catch (e) {
+                    // NOP
+                }
+                return;
         }
-        chrome.tabs.create({url});
     }
 
     _onCommandHelp() {
@@ -697,8 +801,11 @@ class Backend {
         await new Promise((resolve, reject) => {
             chrome.tabs.update(tab.id, {active: true}, () => {
                 const e = chrome.runtime.lastError;
-                if (e) { reject(e); }
-                else { resolve(); }
+                if (e) {
+                    reject(new Error(e.message));
+                } else {
+                    resolve();
+                }
             });
         });
 
@@ -708,19 +815,25 @@ class Backend {
         }
 
         try {
-            const tabWindow = await new Promise((resolve) => {
-                chrome.windows.get(tab.windowId, {}, (tabWindow) => {
+            const tabWindow = await new Promise((resolve, reject) => {
+                chrome.windows.get(tab.windowId, {}, (value) => {
                     const e = chrome.runtime.lastError;
-                    if (e) { reject(e); }
-                    else { resolve(tabWindow); }
+                    if (e) {
+                        reject(new Error(e.message));
+                    } else {
+                        resolve(value);
+                    }
                 });
             });
             if (!tabWindow.focused) {
                 await new Promise((resolve, reject) => {
                     chrome.windows.update(tab.windowId, {focused: true}, () => {
                         const e = chrome.runtime.lastError;
-                        if (e) { reject(e); }
-                        else { resolve(); }
+                        if (e) {
+                            reject(new Error(e.message));
+                        } else {
+                            resolve();
+                        }
                     });
                 });
             }
@@ -777,7 +890,9 @@ Backend._messageHandlers = new Map([
     ['getEnvironmentInfo', (self, ...args) => self._onApiGetEnvironmentInfo(...args)],
     ['clipboardGet', (self, ...args) => self._onApiClipboardGet(...args)],
     ['getDisplayTemplatesHtml', (self, ...args) => self._onApiGetDisplayTemplatesHtml(...args)],
-    ['getZoom', (self, ...args) => self._onApiGetZoom(...args)]
+    ['getQueryParserTemplatesHtml', (self, ...args) => self._onApiGetQueryParserTemplatesHtml(...args)],
+    ['getZoom', (self, ...args) => self._onApiGetZoom(...args)],
+    ['getMessageToken', (self, ...args) => self._onApiGetMessageToken(...args)]
 ]);
 
 Backend._commandHandlers = new Map([
diff --git a/ext/bg/js/clipboard-monitor.js b/ext/bg/js/clipboard-monitor.js
new file mode 100644
index 00000000..c2f41385
--- /dev/null
+++ b/ext/bg/js/clipboard-monitor.js
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*global apiClipboardGet, jpIsStringPartiallyJapanese*/
+
+class ClipboardMonitor {
+    constructor() {
+        this.timerId = null;
+        this.timerToken = null;
+        this.interval = 250;
+        this.previousText = null;
+    }
+
+    onClipboardText(_text) {
+        throw new Error('Override me');
+    }
+
+    start() {
+        this.stop();
+
+        // The token below is used as a unique identifier to ensure that a new clipboard monitor
+        // hasn't been started during the await call. The check below the await apiClipboardGet()
+        // call will exit early if the reference has changed.
+        const token = {};
+        const intervalCallback = async () => {
+            this.timerId = null;
+
+            let text = null;
+            try {
+                text = await apiClipboardGet();
+            } catch (e) {
+                // NOP
+            }
+            if (this.timerToken !== token) { return; }
+
+            if (
+                typeof text === 'string' &&
+                (text = text.trim()).length > 0 &&
+                text !== this.previousText
+            ) {
+                this.previousText = text;
+                if (jpIsStringPartiallyJapanese(text)) {
+                    this.onClipboardText(text);
+                }
+            }
+
+            this.timerId = setTimeout(intervalCallback, this.interval);
+        };
+
+        this.timerToken = token;
+
+        intervalCallback();
+    }
+
+    stop() {
+        this.timerToken = null;
+        if (this.timerId !== null) {
+            clearTimeout(this.timerId);
+            this.timerId = null;
+        }
+    }
+
+    setPreviousText(text) {
+        this.previousText = text;
+    }
+}
diff --git a/ext/bg/js/context.js b/ext/bg/js/context.js
index 834174bf..bec964fb 100644
--- a/ext/bg/js/context.js
+++ b/ext/bg/js/context.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiCommandExec, apiGetEnvironmentInfo, apiOptionsGet*/
 
 function showExtensionInfo() {
     const node = document.getElementById('extension-info');
@@ -30,12 +31,12 @@ function setupButtonEvents(selector, command, url) {
     for (const node of nodes) {
         node.addEventListener('click', (e) => {
             if (e.button !== 0) { return; }
-            apiCommandExec(command, {newTab: e.ctrlKey});
+            apiCommandExec(command, {mode: e.ctrlKey ? 'newTab' : 'existingOrNewTab'});
             e.preventDefault();
         }, false);
         node.addEventListener('auxclick', (e) => {
             if (e.button !== 1) { return; }
-            apiCommandExec(command, {newTab: true});
+            apiCommandExec(command, {mode: 'newTab'});
             e.preventDefault();
         }, false);
 
diff --git a/ext/bg/js/database.js b/ext/bg/js/database.js
index e87cc64b..558f3ceb 100644
--- a/ext/bg/js/database.js
+++ b/ext/bg/js/database.js
@@ -16,20 +16,24 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global dictFieldSplit, requestJson, JsonSchema, JSZip*/
 
 class Database {
     constructor() {
         this.db = null;
+        this._schemas = new Map();
     }
 
+    // Public
+
     async prepare() {
         if (this.db !== null) {
             throw new Error('Database already initialized');
         }
 
         try {
-            this.db = await Database.open('dict', 5, (db, transaction, oldVersion) => {
-                Database.upgrade(db, transaction, oldVersion, [
+            this.db = await Database._open('dict', 5, (db, transaction, oldVersion) => {
+                Database._upgrade(db, transaction, oldVersion, [
                     {
                         version: 2,
                         stores: {
@@ -95,18 +99,24 @@ class Database {
         }
     }
 
+    async close() {
+        this._validate();
+        this.db.close();
+        this.db = null;
+    }
+
     async purge() {
-        this.validate();
+        this._validate();
 
         this.db.close();
-        await Database.deleteDatabase(this.db.name);
+        await Database._deleteDatabase(this.db.name);
         this.db = null;
 
         await this.prepare();
     }
 
     async deleteDictionary(dictionaryName, onProgress, progressSettings) {
-        this.validate();
+        this._validate();
 
         const targets = [
             ['dictionaries', 'title'],
@@ -133,22 +143,22 @@ class Database {
             const dbObjectStore = dbTransaction.objectStore(objectStoreName);
             const dbIndex = dbObjectStore.index(index);
             const only = IDBKeyRange.only(dictionaryName);
-            promises.push(Database.deleteValues(dbObjectStore, dbIndex, only, onProgress, progressData, progressRate));
+            promises.push(Database._deleteValues(dbObjectStore, dbIndex, only, onProgress, progressData, progressRate));
         }
 
         await Promise.all(promises);
     }
 
-    async findTermsBulk(termList, titles, wildcard) {
-        this.validate();
+    async findTermsBulk(termList, dictionaries, wildcard) {
+        this._validate();
 
         const promises = [];
-        const visited = {};
+        const visited = new Set();
         const results = [];
         const processRow = (row, index) => {
-            if (titles.includes(row.dictionary) && !hasOwn(visited, row.id)) {
-                visited[row.id] = true;
-                results.push(Database.createTerm(row, index));
+            if (dictionaries.has(row.dictionary) && !visited.has(row.id)) {
+                visited.add(row.id);
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -164,8 +174,8 @@ class Database {
             const term = prefixWildcard ? stringReverse(termList[i]) : termList[i];
             const query = useWildcard ? IDBKeyRange.bound(term, `${term}\uffff`, false, false) : IDBKeyRange.only(term);
             promises.push(
-                Database.getAll(dbIndex1, query, i, processRow),
-                Database.getAll(dbIndex2, query, i, processRow)
+                Database._getAll(dbIndex1, query, i, processRow),
+                Database._getAll(dbIndex2, query, i, processRow)
             );
         }
 
@@ -174,14 +184,14 @@ class Database {
         return results;
     }
 
-    async findTermsExactBulk(termList, readingList, titles) {
-        this.validate();
+    async findTermsExactBulk(termList, readingList, dictionaries) {
+        this._validate();
 
         const promises = [];
         const results = [];
         const processRow = (row, index) => {
-            if (row.reading === readingList[index] && titles.includes(row.dictionary)) {
-                results.push(Database.createTerm(row, index));
+            if (row.reading === readingList[index] && dictionaries.has(row.dictionary)) {
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -191,7 +201,7 @@ class Database {
 
         for (let i = 0; i < termList.length; ++i) {
             const only = IDBKeyRange.only(termList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
         }
 
         await Promise.all(promises);
@@ -200,13 +210,13 @@ class Database {
     }
 
     async findTermsBySequenceBulk(sequenceList, mainDictionary) {
-        this.validate();
+        this._validate();
 
         const promises = [];
         const results = [];
         const processRow = (row, index) => {
             if (row.dictionary === mainDictionary) {
-                results.push(Database.createTerm(row, index));
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -216,7 +226,7 @@ class Database {
 
         for (let i = 0; i < sequenceList.length; ++i) {
             const only = IDBKeyRange.only(sequenceList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
         }
 
         await Promise.all(promises);
@@ -224,52 +234,27 @@ class Database {
         return results;
     }
 
-    async findTermMetaBulk(termList, titles) {
-        return this.findGenericBulk('termMeta', 'expression', termList, titles, Database.createTermMeta);
+    async findTermMetaBulk(termList, dictionaries) {
+        return this._findGenericBulk('termMeta', 'expression', termList, dictionaries, Database._createTermMeta);
     }
 
-    async findKanjiBulk(kanjiList, titles) {
-        return this.findGenericBulk('kanji', 'character', kanjiList, titles, Database.createKanji);
+    async findKanjiBulk(kanjiList, dictionaries) {
+        return this._findGenericBulk('kanji', 'character', kanjiList, dictionaries, Database._createKanji);
     }
 
-    async findKanjiMetaBulk(kanjiList, titles) {
-        return this.findGenericBulk('kanjiMeta', 'character', kanjiList, titles, Database.createKanjiMeta);
-    }
-
-    async findGenericBulk(tableName, indexName, indexValueList, titles, createResult) {
-        this.validate();
-
-        const promises = [];
-        const results = [];
-        const processRow = (row, index) => {
-            if (titles.includes(row.dictionary)) {
-                results.push(createResult(row, index));
-            }
-        };
-
-        const dbTransaction = this.db.transaction([tableName], 'readonly');
-        const dbTerms = dbTransaction.objectStore(tableName);
-        const dbIndex = dbTerms.index(indexName);
-
-        for (let i = 0; i < indexValueList.length; ++i) {
-            const only = IDBKeyRange.only(indexValueList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
-        }
-
-        await Promise.all(promises);
-
-        return results;
+    async findKanjiMetaBulk(kanjiList, dictionaries) {
+        return this._findGenericBulk('kanjiMeta', 'character', kanjiList, dictionaries, Database._createKanjiMeta);
     }
 
     async findTagForTitle(name, title) {
-        this.validate();
+        this._validate();
 
         let result = null;
         const dbTransaction = this.db.transaction(['tagMeta'], 'readonly');
         const dbTerms = dbTransaction.objectStore('tagMeta');
         const dbIndex = dbTerms.index('name');
         const only = IDBKeyRange.only(name);
-        await Database.getAll(dbIndex, only, null, (row) => {
+        await Database._getAll(dbIndex, only, null, (row) => {
             if (title === row.dictionary) {
                 result = row;
             }
@@ -279,19 +264,19 @@ class Database {
     }
 
     async getDictionaryInfo() {
-        this.validate();
+        this._validate();
 
         const results = [];
         const dbTransaction = this.db.transaction(['dictionaries'], 'readonly');
         const dbDictionaries = dbTransaction.objectStore('dictionaries');
 
-        await Database.getAll(dbDictionaries, null, null, (info) => results.push(info));
+        await Database._getAll(dbDictionaries, null, null, (info) => results.push(info));
 
         return results;
     }
 
     async getDictionaryCounts(dictionaryNames, getTotal) {
-        this.validate();
+        this._validate();
 
         const objectStoreNames = [
             'kanji',
@@ -312,7 +297,7 @@ class Database {
 
         // Query is required for Edge, otherwise index.count throws an exception.
         const query1 = IDBKeyRange.lowerBound('', false);
-        const totalPromise = getTotal ? Database.getCounts(targets, query1) : null;
+        const totalPromise = getTotal ? Database._getCounts(targets, query1) : null;
 
         const counts = [];
         const countPromises = [];
@@ -320,7 +305,7 @@ class Database {
             counts.push(null);
             const index = i;
             const query2 = IDBKeyRange.only(dictionaryNames[i]);
-            const countPromise = Database.getCounts(targets, query2).then((v) => counts[index] = v);
+            const countPromise = Database._getCounts(targets, query2).then((v) => counts[index] = v);
             countPromises.push(countPromise);
         }
         await Promise.all(countPromises);
@@ -332,278 +317,287 @@ class Database {
         return result;
     }
 
-    async importDictionary(archive, progressCallback, details) {
-        this.validate();
+    async importDictionary(archiveSource, onProgress, details) {
+        this._validate();
+        const db = this.db;
+        const hasOnProgress = (typeof onProgress === 'function');
 
-        const errors = [];
-        const prefixWildcardsSupported = details.prefixWildcardsSupported;
+        // Read archive
+        const archive = await JSZip.loadAsync(archiveSource);
 
-        const maxTransactionLength = 1000;
-        const bulkAdd = async (objectStoreName, items, total, current) => {
-            const db = this.db;
-            for (let i = 0; i < items.length; i += maxTransactionLength) {
-                if (progressCallback) {
-                    progressCallback(total, current + i / items.length);
-                }
+        // Read and validate index
+        const indexFileName = 'index.json';
+        const indexFile = archive.files[indexFileName];
+        if (!indexFile) {
+            throw new Error('No dictionary index found in archive');
+        }
 
-                try {
-                    const count = Math.min(maxTransactionLength, items.length - i);
-                    const transaction = db.transaction([objectStoreName], 'readwrite');
-                    const objectStore = transaction.objectStore(objectStoreName);
-                    await Database.bulkAdd(objectStore, items, i, count);
-                } catch (e) {
-                    errors.push(e);
-                }
-            }
-        };
+        const index = JSON.parse(await indexFile.async('string'));
 
-        const indexDataLoaded = async (summary) => {
-            if (summary.version > 3) {
-                throw new Error('Unsupported dictionary version');
-            }
+        const indexSchema = await this._getSchema('/bg/data/dictionary-index-schema.json');
+        Database._validateJsonSchema(index, indexSchema, indexFileName);
 
-            const db = this.db;
-            const dbCountTransaction = db.transaction(['dictionaries'], 'readonly');
-            const dbIndex = dbCountTransaction.objectStore('dictionaries').index('title');
-            const only = IDBKeyRange.only(summary.title);
-            const count = await Database.getCount(dbIndex, only);
+        const dictionaryTitle = index.title;
+        const version = index.format || index.version;
 
-            if (count > 0) {
-                throw new Error('Dictionary is already imported');
-            }
+        if (!dictionaryTitle || !index.revision) {
+            throw new Error('Unrecognized dictionary format');
+        }
 
-            const transaction = db.transaction(['dictionaries'], 'readwrite');
-            const objectStore = transaction.objectStore('dictionaries');
-            await Database.bulkAdd(objectStore, [summary], 0, 1);
-        };
+        // Verify database is not already imported
+        if (await this._dictionaryExists(dictionaryTitle)) {
+            throw new Error('Dictionary is already imported');
+        }
 
-        const termDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            if (summary.version === 1) {
-                for (const [expression, reading, definitionTags, rules, score, ...glossary] of entries) {
-                    rows.push({
-                        expression,
-                        reading,
-                        definitionTags,
-                        rules,
-                        score,
-                        glossary,
-                        dictionary: summary.title
-                    });
-                }
+        // Data format converters
+        const convertTermBankEntry = (entry) => {
+            if (version === 1) {
+                const [expression, reading, definitionTags, rules, score, ...glossary] = entry;
+                return {expression, reading, definitionTags, rules, score, glossary};
             } else {
-                for (const [expression, reading, definitionTags, rules, score, glossary, sequence, termTags] of entries) {
-                    rows.push({
-                        expression,
-                        reading,
-                        definitionTags,
-                        rules,
-                        score,
-                        glossary,
-                        sequence,
-                        termTags,
-                        dictionary: summary.title
-                    });
-                }
-            }
-
-            if (prefixWildcardsSupported) {
-                for (const row of rows) {
-                    row.expressionReverse = stringReverse(row.expression);
-                    row.readingReverse = stringReverse(row.reading);
-                }
+                const [expression, reading, definitionTags, rules, score, glossary, sequence, termTags] = entry;
+                return {expression, reading, definitionTags, rules, score, glossary, sequence, termTags};
             }
+        };
 
-            await bulkAdd('terms', rows, total, current);
+        const convertTermMetaBankEntry = (entry) => {
+            const [expression, mode, data] = entry;
+            return {expression, mode, data};
         };
 
-        const termMetaDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [expression, mode, data] of entries) {
-                rows.push({
-                    expression,
-                    mode,
-                    data,
-                    dictionary: summary.title
-                });
+        const convertKanjiBankEntry = (entry) => {
+            if (version === 1) {
+                const [character, onyomi, kunyomi, tags, ...meanings] = entry;
+                return {character, onyomi, kunyomi, tags, meanings};
+            } else {
+                const [character, onyomi, kunyomi, tags, meanings, stats] = entry;
+                return {character, onyomi, kunyomi, tags, meanings, stats};
             }
+        };
 
-            await bulkAdd('termMeta', rows, total, current);
+        const convertKanjiMetaBankEntry = (entry) => {
+            const [character, mode, data] = entry;
+            return {character, mode, data};
         };
 
-        const kanjiDataLoaded = async (summary, entries, total, current)  => {
-            const rows = [];
-            if (summary.version === 1) {
-                for (const [character, onyomi, kunyomi, tags, ...meanings] of entries) {
-                    rows.push({
-                        character,
-                        onyomi,
-                        kunyomi,
-                        tags,
-                        meanings,
-                        dictionary: summary.title
-                    });
-                }
-            } else {
-                for (const [character, onyomi, kunyomi, tags, meanings, stats] of entries) {
-                    rows.push({
-                        character,
-                        onyomi,
-                        kunyomi,
-                        tags,
-                        meanings,
-                        stats,
-                        dictionary: summary.title
-                    });
+        const convertTagBankEntry = (entry) => {
+            const [name, category, order, notes, score] = entry;
+            return {name, category, order, notes, score};
+        };
+
+        // Archive file reading
+        const readFileSequence = async (fileNameFormat, convertEntry, schema) => {
+            const results = [];
+            for (let i = 1; true; ++i) {
+                const fileName = fileNameFormat.replace(/\?/, `${i}`);
+                const file = archive.files[fileName];
+                if (!file) { break; }
+
+                const entries = JSON.parse(await file.async('string'));
+                Database._validateJsonSchema(entries, schema, fileName);
+
+                for (let entry of entries) {
+                    entry = convertEntry(entry);
+                    entry.dictionary = dictionaryTitle;
+                    results.push(entry);
                 }
             }
-
-            await bulkAdd('kanji', rows, total, current);
+            return results;
         };
 
-        const kanjiMetaDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [character, mode, data] of entries) {
-                rows.push({
-                    character,
-                    mode,
-                    data,
-                    dictionary: summary.title
-                });
+        // Load schemas
+        const dataBankSchemaPaths = this.constructor._getDataBankSchemaPaths(version);
+        const dataBankSchemas = await Promise.all(dataBankSchemaPaths.map((path) => this._getSchema(path)));
+
+        // Load data
+        const termList      = await readFileSequence('term_bank_?.json',       convertTermBankEntry,      dataBankSchemas[0]);
+        const termMetaList  = await readFileSequence('term_meta_bank_?.json',  convertTermMetaBankEntry,  dataBankSchemas[1]);
+        const kanjiList     = await readFileSequence('kanji_bank_?.json',      convertKanjiBankEntry,     dataBankSchemas[2]);
+        const kanjiMetaList = await readFileSequence('kanji_meta_bank_?.json', convertKanjiMetaBankEntry, dataBankSchemas[3]);
+        const tagList       = await readFileSequence('tag_bank_?.json',        convertTagBankEntry,       dataBankSchemas[4]);
+
+        // Old tags
+        const indexTagMeta = index.tagMeta;
+        if (typeof indexTagMeta === 'object' && indexTagMeta !== null) {
+            for (const name of Object.keys(indexTagMeta)) {
+                const {category, order, notes, score} = indexTagMeta[name];
+                tagList.push({name, category, order, notes, score});
             }
+        }
 
-            await bulkAdd('kanjiMeta', rows, total, current);
-        };
-
-        const tagDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [name, category, order, notes, score] of entries) {
-                const row = dictTagSanitize({
-                    name,
-                    category,
-                    order,
-                    notes,
-                    score,
-                    dictionary: summary.title
-                });
-
-                rows.push(row);
+        // Prefix wildcard support
+        const prefixWildcardsSupported = !!details.prefixWildcardsSupported;
+        if (prefixWildcardsSupported) {
+            for (const entry of termList) {
+                entry.expressionReverse = stringReverse(entry.expression);
+                entry.readingReverse = stringReverse(entry.reading);
             }
+        }
 
-            await bulkAdd('tagMeta', rows, total, current);
+        // Add dictionary
+        const summary = {
+            title: dictionaryTitle,
+            revision: index.revision,
+            sequenced: index.sequenced,
+            version,
+            prefixWildcardsSupported
         };
 
-        const result = await Database.importDictionaryZip(
-            archive,
-            indexDataLoaded,
-            termDataLoaded,
-            termMetaDataLoaded,
-            kanjiDataLoaded,
-            kanjiMetaDataLoaded,
-            tagDataLoaded,
-            details
+        {
+            const transaction = db.transaction(['dictionaries'], 'readwrite');
+            const objectStore = transaction.objectStore('dictionaries');
+            await Database._bulkAdd(objectStore, [summary], 0, 1);
+        }
+
+        // Add data
+        const errors = [];
+        const total = (
+            termList.length +
+            termMetaList.length +
+            kanjiList.length +
+            kanjiMetaList.length +
+            tagList.length
         );
+        let loadedCount = 0;
+        const maxTransactionLength = 1000;
+
+        const bulkAdd = async (objectStoreName, entries) => {
+            const ii = entries.length;
+            for (let i = 0; i < ii; i += maxTransactionLength) {
+                const count = Math.min(maxTransactionLength, ii - i);
+
+                try {
+                    const transaction = db.transaction([objectStoreName], 'readwrite');
+                    const objectStore = transaction.objectStore(objectStoreName);
+                    await Database._bulkAdd(objectStore, entries, i, count);
+                } catch (e) {
+                    errors.push(e);
+                }
 
-        return {result, errors};
+                loadedCount += count;
+                if (hasOnProgress) {
+                    onProgress(total, loadedCount);
+                }
+            }
+        };
+
+        await bulkAdd('terms', termList);
+        await bulkAdd('termMeta', termMetaList);
+        await bulkAdd('kanji', kanjiList);
+        await bulkAdd('kanjiMeta', kanjiMetaList);
+        await bulkAdd('tagMeta', tagList);
+
+        return {result: summary, errors};
     }
 
-    validate() {
+    // Private
+
+    _validate() {
         if (this.db === null) {
             throw new Error('Database not initialized');
         }
     }
 
-    static async importDictionaryZip(
-        archive,
-        indexDataLoaded,
-        termDataLoaded,
-        termMetaDataLoaded,
-        kanjiDataLoaded,
-        kanjiMetaDataLoaded,
-        tagDataLoaded,
-        details
-    ) {
-        const zip = await JSZip.loadAsync(archive);
-
-        const indexFile = zip.files['index.json'];
-        if (!indexFile) {
-            throw new Error('No dictionary index found in archive');
+    async _getSchema(fileName) {
+        let schemaPromise = this._schemas.get(fileName);
+        if (typeof schemaPromise !== 'undefined') {
+            return schemaPromise;
         }
 
-        const index = JSON.parse(await indexFile.async('string'));
-        if (!index.title || !index.revision) {
-            throw new Error('Unrecognized dictionary format');
+        schemaPromise = requestJson(chrome.runtime.getURL(fileName), 'GET');
+        this._schemas.set(fileName, schemaPromise);
+        return schemaPromise;
+    }
+
+    static _validateJsonSchema(value, schema, fileName) {
+        try {
+            JsonSchema.validate(value, schema);
+        } catch (e) {
+            throw Database._formatSchemaError(e, fileName);
         }
+    }
 
-        const summary = {
-            title: index.title,
-            revision: index.revision,
-            sequenced: index.sequenced,
-            version: index.format || index.version,
-            prefixWildcardsSupported: !!details.prefixWildcardsSupported
-        };
+    static _formatSchemaError(e, fileName) {
+        const valuePathString = Database._getSchemaErrorPathString(e.info.valuePath, 'dictionary');
+        const schemaPathString = Database._getSchemaErrorPathString(e.info.schemaPath, 'schema');
 
-        await indexDataLoaded(summary);
+        const e2 = new Error(`Dictionary has invalid data in '${fileName}' for value '${valuePathString}', validated against '${schemaPathString}': ${e.message}`);
+        e2.data = e;
 
-        const buildTermBankName      = (index) => `term_bank_${index + 1}.json`;
-        const buildTermMetaBankName  = (index) => `term_meta_bank_${index + 1}.json`;
-        const buildKanjiBankName     = (index) => `kanji_bank_${index + 1}.json`;
-        const buildKanjiMetaBankName = (index) => `kanji_meta_bank_${index + 1}.json`;
-        const buildTagBankName       = (index) => `tag_bank_${index + 1}.json`;
+        return e2;
+    }
 
-        const countBanks = (namer) => {
-            let count = 0;
-            while (zip.files[namer(count)]) {
-                ++count;
+    static _getSchemaErrorPathString(infoList, base='') {
+        let result = base;
+        for (const [part] of infoList) {
+            switch (typeof part) {
+                case 'string':
+                    if (result.length > 0) {
+                        result += '.';
+                    }
+                    result += part;
+                    break;
+                case 'number':
+                    result += `[${part}]`;
+                    break;
             }
+        }
+        return result;
+    }
 
-            return count;
-        };
+    static _getDataBankSchemaPaths(version) {
+        const termBank = (
+            version === 1 ?
+            '/bg/data/dictionary-term-bank-v1-schema.json' :
+            '/bg/data/dictionary-term-bank-v3-schema.json'
+        );
+        const termMetaBank = '/bg/data/dictionary-term-meta-bank-v3-schema.json';
+        const kanjiBank = (
+            version === 1 ?
+            '/bg/data/dictionary-kanji-bank-v1-schema.json' :
+            '/bg/data/dictionary-kanji-bank-v3-schema.json'
+        );
+        const kanjiMetaBank = '/bg/data/dictionary-kanji-meta-bank-v3-schema.json';
+        const tagBank = '/bg/data/dictionary-tag-bank-v3-schema.json';
 
-        const termBankCount      = countBanks(buildTermBankName);
-        const termMetaBankCount  = countBanks(buildTermMetaBankName);
-        const kanjiBankCount     = countBanks(buildKanjiBankName);
-        const kanjiMetaBankCount = countBanks(buildKanjiMetaBankName);
-        const tagBankCount       = countBanks(buildTagBankName);
-
-        let bankLoadedCount = 0;
-        let bankTotalCount =
-            termBankCount +
-            termMetaBankCount +
-            kanjiBankCount +
-            kanjiMetaBankCount +
-            tagBankCount;
-
-        if (tagDataLoaded && index.tagMeta) {
-            const bank = [];
-            for (const name in index.tagMeta) {
-                const tag = index.tagMeta[name];
-                bank.push([name, tag.category, tag.order, tag.notes, tag.score]);
-            }
+        return [termBank, termMetaBank, kanjiBank, kanjiMetaBank, tagBank];
+    }
 
-            tagDataLoaded(summary, bank, ++bankTotalCount, bankLoadedCount++);
-        }
+    async _dictionaryExists(title) {
+        const db = this.db;
+        const dbCountTransaction = db.transaction(['dictionaries'], 'readonly');
+        const dbIndex = dbCountTransaction.objectStore('dictionaries').index('title');
+        const only = IDBKeyRange.only(title);
+        const count = await Database._getCount(dbIndex, only);
+        return count > 0;
+    }
 
-        const loadBank = async (summary, namer, count, callback) => {
-            if (callback) {
-                for (let i = 0; i < count; ++i) {
-                    const bankFile = zip.files[namer(i)];
-                    const bank = JSON.parse(await bankFile.async('string'));
-                    await callback(summary, bank, bankTotalCount, bankLoadedCount++);
-                }
+    async _findGenericBulk(tableName, indexName, indexValueList, dictionaries, createResult) {
+        this._validate();
+
+        const promises = [];
+        const results = [];
+        const processRow = (row, index) => {
+            if (dictionaries.has(row.dictionary)) {
+                results.push(createResult(row, index));
             }
         };
 
-        await loadBank(summary, buildTermBankName, termBankCount, termDataLoaded);
-        await loadBank(summary, buildTermMetaBankName, termMetaBankCount, termMetaDataLoaded);
-        await loadBank(summary, buildKanjiBankName, kanjiBankCount, kanjiDataLoaded);
-        await loadBank(summary, buildKanjiMetaBankName, kanjiMetaBankCount, kanjiMetaDataLoaded);
-        await loadBank(summary, buildTagBankName, tagBankCount, tagDataLoaded);
+        const dbTransaction = this.db.transaction([tableName], 'readonly');
+        const dbTerms = dbTransaction.objectStore(tableName);
+        const dbIndex = dbTerms.index(indexName);
+
+        for (let i = 0; i < indexValueList.length; ++i) {
+            const only = IDBKeyRange.only(indexValueList[i]);
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
+        }
+
+        await Promise.all(promises);
 
-        return summary;
+        return results;
     }
 
-    static createTerm(row, index) {
+    static _createTerm(row, index) {
         return {
             index,
             expression: row.expression,
@@ -619,7 +613,7 @@ class Database {
         };
     }
 
-    static createKanji(row, index) {
+    static _createKanji(row, index) {
         return {
             index,
             character: row.character,
@@ -632,20 +626,20 @@ class Database {
         };
     }
 
-    static createTermMeta({expression, mode, data, dictionary}, index) {
+    static _createTermMeta({expression, mode, data, dictionary}, index) {
         return {expression, mode, data, dictionary, index};
     }
 
-    static createKanjiMeta({character, mode, data, dictionary}, index) {
+    static _createKanjiMeta({character, mode, data, dictionary}, index) {
         return {character, mode, data, dictionary, index};
     }
 
-    static getAll(dbIndex, query, context, processRow) {
-        const fn = typeof dbIndex.getAll === 'function' ? Database.getAllFast : Database.getAllUsingCursor;
+    static _getAll(dbIndex, query, context, processRow) {
+        const fn = typeof dbIndex.getAll === 'function' ? Database._getAllFast : Database._getAllUsingCursor;
         return fn(dbIndex, query, context, processRow);
     }
 
-    static getAllFast(dbIndex, query, context, processRow) {
+    static _getAllFast(dbIndex, query, context, processRow) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.getAll(query);
             request.onerror = (e) => reject(e);
@@ -658,7 +652,7 @@ class Database {
         });
     }
 
-    static getAllUsingCursor(dbIndex, query, context, processRow) {
+    static _getAllUsingCursor(dbIndex, query, context, processRow) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.openCursor(query, 'next');
             request.onerror = (e) => reject(e);
@@ -674,18 +668,18 @@ class Database {
         });
     }
 
-    static getCounts(targets, query) {
+    static _getCounts(targets, query) {
         const countPromises = [];
         const counts = {};
         for (const [objectStoreName, index] of targets) {
             const n = objectStoreName;
-            const countPromise = Database.getCount(index, query).then((count) => counts[n] = count);
+            const countPromise = Database._getCount(index, query).then((count) => counts[n] = count);
             countPromises.push(countPromise);
         }
         return Promise.all(countPromises).then(() => counts);
     }
 
-    static getCount(dbIndex, query) {
+    static _getCount(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.count(query);
             request.onerror = (e) => reject(e);
@@ -693,12 +687,12 @@ class Database {
         });
     }
 
-    static getAllKeys(dbIndex, query) {
-        const fn = typeof dbIndex.getAllKeys === 'function' ? Database.getAllKeysFast : Database.getAllKeysUsingCursor;
+    static _getAllKeys(dbIndex, query) {
+        const fn = typeof dbIndex.getAllKeys === 'function' ? Database._getAllKeysFast : Database._getAllKeysUsingCursor;
         return fn(dbIndex, query);
     }
 
-    static getAllKeysFast(dbIndex, query) {
+    static _getAllKeysFast(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.getAllKeys(query);
             request.onerror = (e) => reject(e);
@@ -706,7 +700,7 @@ class Database {
         });
     }
 
-    static getAllKeysUsingCursor(dbIndex, query) {
+    static _getAllKeysUsingCursor(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const primaryKeys = [];
             const request = dbIndex.openKeyCursor(query, 'next');
@@ -723,9 +717,9 @@ class Database {
         });
     }
 
-    static async deleteValues(dbObjectStore, dbIndex, query, onProgress, progressData, progressRate) {
+    static async _deleteValues(dbObjectStore, dbIndex, query, onProgress, progressData, progressRate) {
         const hasProgress = (typeof onProgress === 'function');
-        const count = await Database.getCount(dbIndex, query);
+        const count = await Database._getCount(dbIndex, query);
         ++progressData.storesProcesed;
         progressData.count += count;
         if (hasProgress) {
@@ -744,16 +738,16 @@ class Database {
         );
 
         const promises = [];
-        const primaryKeys = await Database.getAllKeys(dbIndex, query);
+        const primaryKeys = await Database._getAllKeys(dbIndex, query);
         for (const key of primaryKeys) {
-            const promise = Database.deleteValue(dbObjectStore, key).then(onValueDeleted);
+            const promise = Database._deleteValue(dbObjectStore, key).then(onValueDeleted);
             promises.push(promise);
         }
 
         await Promise.all(promises);
     }
 
-    static deleteValue(dbObjectStore, key) {
+    static _deleteValue(dbObjectStore, key) {
         return new Promise((resolve, reject) => {
             const request = dbObjectStore.delete(key);
             request.onerror = (e) => reject(e);
@@ -761,7 +755,7 @@ class Database {
         });
     }
 
-    static bulkAdd(objectStore, items, start, count) {
+    static _bulkAdd(objectStore, items, start, count) {
         return new Promise((resolve, reject) => {
             if (start + count > items.length) {
                 count = items.length - start;
@@ -789,7 +783,7 @@ class Database {
         });
     }
 
-    static open(name, version, onUpgradeNeeded) {
+    static _open(name, version, onUpgradeNeeded) {
         return new Promise((resolve, reject) => {
             const request = window.indexedDB.open(name, version * 10);
 
@@ -807,7 +801,7 @@ class Database {
         });
     }
 
-    static upgrade(db, transaction, oldVersion, upgrades) {
+    static _upgrade(db, transaction, oldVersion, upgrades) {
         for (const {version, stores} of upgrades) {
             if (oldVersion >= version) { continue; }
 
@@ -815,15 +809,15 @@ class Database {
             for (const objectStoreName of objectStoreNames) {
                 const {primaryKey, indices} = stores[objectStoreName];
 
-                const objectStoreNames = transaction.objectStoreNames || db.objectStoreNames;
+                const objectStoreNames2 = transaction.objectStoreNames || db.objectStoreNames;
                 const objectStore = (
-                    Database.listContains(objectStoreNames, objectStoreName) ?
+                    Database._listContains(objectStoreNames2, objectStoreName) ?
                     transaction.objectStore(objectStoreName) :
                     db.createObjectStore(objectStoreName, primaryKey)
                 );
 
                 for (const indexName of indices) {
-                    if (Database.listContains(objectStore.indexNames, indexName)) { continue; }
+                    if (Database._listContains(objectStore.indexNames, indexName)) { continue; }
 
                     objectStore.createIndex(indexName, indexName, {});
                 }
@@ -831,7 +825,7 @@ class Database {
         }
     }
 
-    static deleteDatabase(dbName) {
+    static _deleteDatabase(dbName) {
         return new Promise((resolve, reject) => {
             const request = indexedDB.deleteDatabase(dbName);
             request.onerror = (e) => reject(e);
@@ -839,7 +833,7 @@ class Database {
         });
     }
 
-    static listContains(list, value) {
+    static _listContains(list, value) {
         for (let i = 0, ii = list.length; i < ii; ++i) {
             if (list[i] === value) { return true; }
         }
diff --git a/ext/bg/js/deinflector.js b/ext/bg/js/deinflector.js
index 33b2a8b3..e2ced965 100644
--- a/ext/bg/js/deinflector.js
+++ b/ext/bg/js/deinflector.js
@@ -76,17 +76,19 @@ class Deinflector {
         const ruleTypes = Deinflector.ruleTypes;
         let value = 0;
         for (const rule of rules) {
-            value |= ruleTypes[rule];
+            const ruleBits = ruleTypes.get(rule);
+            if (typeof ruleBits === 'undefined') { continue; }
+            value |= ruleBits;
         }
         return value;
     }
 }
 
-Deinflector.ruleTypes = {
-    'v1':    0b0000001, // Verb ichidan
-    'v5':    0b0000010, // Verb godan
-    'vs':    0b0000100, // Verb suru
-    'vk':    0b0001000, // Verb kuru
-    'adj-i': 0b0010000, // Adjective i
-    'iru':   0b0100000  // Intermediate -iru endings for progressive or perfect tense
-};
+Deinflector.ruleTypes = new Map([
+    ['v1',    0b0000001], // Verb ichidan
+    ['v5',    0b0000010], // Verb godan
+    ['vs',    0b0000100], // Verb suru
+    ['vk',    0b0001000], // Verb kuru
+    ['adj-i', 0b0010000], // Adjective i
+    ['iru',   0b0100000] // Intermediate -iru endings for progressive or perfect tense
+]);
diff --git a/ext/bg/js/dictionary.js b/ext/bg/js/dictionary.js
index 67128725..f5c5b21b 100644
--- a/ext/bg/js/dictionary.js
+++ b/ext/bg/js/dictionary.js
@@ -16,17 +16,21 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiTemplateRender*/
 
 function dictEnabledSet(options) {
-    const dictionaries = {};
-    for (const title in options.dictionaries) {
-        const dictionary = options.dictionaries[title];
-        if (dictionary.enabled) {
-            dictionaries[title] = dictionary;
-        }
+    const enabledDictionaryMap = new Map();
+    const optionsDictionaries = options.dictionaries;
+    for (const title in optionsDictionaries) {
+        if (!hasOwn(optionsDictionaries, title)) { continue; }
+        const dictionary = optionsDictionaries[title];
+        if (!dictionary.enabled) { continue; }
+        enabledDictionaryMap.set(title, {
+            priority: dictionary.priority || 0,
+            allowSecondarySearches: !!dictionary.allowSecondarySearches
+        });
     }
-
-    return dictionaries;
+    return enabledDictionaryMap;
 }
 
 function dictConfigured(options) {
@@ -39,28 +43,15 @@ function dictConfigured(options) {
     return false;
 }
 
-function dictRowsSort(rows, options) {
-    return rows.sort((ra, rb) => {
-        const pa = (options.dictionaries[ra.title] || {}).priority || 0;
-        const pb = (options.dictionaries[rb.title] || {}).priority || 0;
-        if (pa > pb) {
-            return -1;
-        } else if (pa < pb) {
-            return 1;
-        } else {
-            return 0;
-        }
-    });
-}
-
 function dictTermsSort(definitions, dictionaries=null) {
     return definitions.sort((v1, v2) => {
         let i;
         if (dictionaries !== null) {
-            i = (
-                ((dictionaries[v2.dictionary] || {}).priority || 0) -
-                ((dictionaries[v1.dictionary] || {}).priority || 0)
-            );
+            const dictionaryInfo1 = dictionaries.get(v1.dictionary);
+            const dictionaryInfo2 = dictionaries.get(v2.dictionary);
+            const priority1 = typeof dictionaryInfo1 !== 'undefined' ? dictionaryInfo1.priority : 0;
+            const priority2 = typeof dictionaryInfo2 !== 'undefined' ? dictionaryInfo2.priority : 0;
+            i = priority2 - priority1;
             if (i !== 0) { return i; }
         }
 
@@ -78,20 +69,16 @@ function dictTermsSort(definitions, dictionaries=null) {
 }
 
 function dictTermsUndupe(definitions) {
-    const definitionGroups = {};
+    const definitionGroups = new Map();
     for (const definition of definitions) {
-        const definitionExisting = definitionGroups[definition.id];
-        if (!hasOwn(definitionGroups, definition.id) || definition.expression.length > definitionExisting.expression.length) {
-            definitionGroups[definition.id] = definition;
+        const id = definition.id;
+        const definitionExisting = definitionGroups.get(id);
+        if (typeof definitionExisting === 'undefined' || definition.expression.length > definitionExisting.expression.length) {
+            definitionGroups.set(id, definition);
         }
     }
 
-    const definitionsUnique = [];
-    for (const key in definitionGroups) {
-        definitionsUnique.push(definitionGroups[key]);
-    }
-
-    return definitionsUnique;
+    return [...definitionGroups.values()];
 }
 
 function dictTermsCompressTags(definitions) {
@@ -122,35 +109,35 @@ function dictTermsCompressTags(definitions) {
 }
 
 function dictTermsGroup(definitions, dictionaries) {
-    const groups = {};
+    const groups = new Map();
     for (const definition of definitions) {
-        const key = [definition.source, definition.expression];
-        key.push(...definition.reasons);
+        const key = [definition.source, definition.expression, ...definition.reasons];
         if (definition.reading) {
             key.push(definition.reading);
         }
 
         const keyString = key.toString();
-        if (hasOwn(groups, keyString)) {
-            groups[keyString].push(definition);
-        } else {
-            groups[keyString] = [definition];
+        let groupDefinitions = groups.get(keyString);
+        if (typeof groupDefinitions === 'undefined') {
+            groupDefinitions = [];
+            groups.set(keyString, groupDefinitions);
         }
+
+        groupDefinitions.push(definition);
     }
 
     const results = [];
-    for (const key in groups) {
-        const groupDefs = groups[key];
-        const firstDef = groupDefs[0];
-        dictTermsSort(groupDefs, dictionaries);
+    for (const groupDefinitions of groups.values()) {
+        const firstDef = groupDefinitions[0];
+        dictTermsSort(groupDefinitions, dictionaries);
         results.push({
-            definitions: groupDefs,
+            definitions: groupDefinitions,
             expression: firstDef.expression,
             reading: firstDef.reading,
             furiganaSegments: firstDef.furiganaSegments,
             reasons: firstDef.reasons,
             termTags: firstDef.termTags,
-            score: groupDefs.reduce((p, v) => v.score > p ? v.score : p, Number.MIN_SAFE_INTEGER),
+            score: groupDefinitions.reduce((p, v) => v.score > p ? v.score : p, Number.MIN_SAFE_INTEGER),
             source: firstDef.source
         });
     }
@@ -158,14 +145,41 @@ function dictTermsGroup(definitions, dictionaries) {
     return dictTermsSort(results);
 }
 
+function dictAreSetsEqual(set1, set2) {
+    if (set1.size !== set2.size) {
+        return false;
+    }
+
+    for (const value of set1) {
+        if (!set2.has(value)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+function dictGetSetIntersection(set1, set2) {
+    const result = [];
+    for (const value of set1) {
+        if (set2.has(value)) {
+            result.push(value);
+        }
+    }
+    return result;
+}
+
 function dictTermsMergeBySequence(definitions, mainDictionary) {
-    const definitionsBySequence = {'-1': []};
+    const sequencedDefinitions = new Map();
+    const nonSequencedDefinitions = [];
     for (const definition of definitions) {
-        if (mainDictionary === definition.dictionary && definition.sequence >= 0) {
-            if (!definitionsBySequence[definition.sequence]) {
-                definitionsBySequence[definition.sequence] = {
+        const sequence = definition.sequence;
+        if (mainDictionary === definition.dictionary && sequence >= 0) {
+            let sequencedDefinition = sequencedDefinitions.get(sequence);
+            if (typeof sequencedDefinition === 'undefined') {
+                sequencedDefinition = {
                     reasons: definition.reasons,
-                    score: Number.MIN_SAFE_INTEGER,
+                    score: definition.score,
                     expression: new Set(),
                     reading: new Set(),
                     expressions: new Map(),
@@ -173,100 +187,115 @@ function dictTermsMergeBySequence(definitions, mainDictionary) {
                     dictionary: definition.dictionary,
                     definitions: []
                 };
+                sequencedDefinitions.set(sequence, sequencedDefinition);
+            } else {
+                sequencedDefinition.score = Math.max(sequencedDefinition.score, definition.score);
             }
-            const score = Math.max(definitionsBySequence[definition.sequence].score, definition.score);
-            definitionsBySequence[definition.sequence].score = score;
         } else {
-            definitionsBySequence['-1'].push(definition);
+            nonSequencedDefinitions.push(definition);
         }
     }
 
-    return definitionsBySequence;
+    return [sequencedDefinitions, nonSequencedDefinitions];
 }
 
-function dictTermsMergeByGloss(result, definitions, appendTo, mergedIndices) {
-    const definitionsByGloss = appendTo || {};
-    for (const [index, definition] of definitions.entries()) {
-        if (appendTo) {
-            let match = false;
-            for (const expression of result.expressions.keys()) {
-                if (definition.expression === expression) {
-                    for (const reading of result.expressions.get(expression).keys()) {
-                        if (definition.reading === reading) {
-                            match = true;
-                            break;
-                        }
-                    }
-                }
-                if (match) {
-                    break;
-                }
-            }
+function dictTermsMergeByGloss(result, definitions, appendTo=null, mergedIndices=null) {
+    const definitionsByGloss = appendTo !== null ? appendTo : new Map();
 
-            if (!match) {
-                continue;
-            } else if (mergedIndices) {
+    const resultExpressionsMap = result.expressions;
+    const resultExpressionSet = result.expression;
+    const resultReadingSet = result.reading;
+    const resultSource = result.source;
+
+    for (const [index, definition] of definitions.entries()) {
+        const {expression, reading} = definition;
+
+        if (mergedIndices !== null) {
+            const expressionMap = resultExpressionsMap.get(expression);
+            if (
+                typeof expressionMap !== 'undefined' &&
+                typeof expressionMap.get(reading) !== 'undefined'
+            ) {
                 mergedIndices.add(index);
+            } else {
+                continue;
             }
         }
 
         const gloss = JSON.stringify(definition.glossary.concat(definition.dictionary));
-        if (!definitionsByGloss[gloss]) {
-            definitionsByGloss[gloss] = {
+        let glossDefinition = definitionsByGloss.get(gloss);
+        if (typeof glossDefinition === 'undefined') {
+            glossDefinition = {
                 expression: new Set(),
                 reading: new Set(),
                 definitionTags: [],
                 glossary: definition.glossary,
-                source: result.source,
+                source: resultSource,
                 reasons: [],
                 score: definition.score,
                 id: definition.id,
                 dictionary: definition.dictionary
             };
+            definitionsByGloss.set(gloss, glossDefinition);
         }
 
-        definitionsByGloss[gloss].expression.add(definition.expression);
-        definitionsByGloss[gloss].reading.add(definition.reading);
+        glossDefinition.expression.add(expression);
+        glossDefinition.reading.add(reading);
 
-        result.expression.add(definition.expression);
-        result.reading.add(definition.reading);
+        resultExpressionSet.add(expression);
+        resultReadingSet.add(reading);
 
         for (const tag of definition.definitionTags) {
-            if (!definitionsByGloss[gloss].definitionTags.find((existingTag) => existingTag.name === tag.name)) {
-                definitionsByGloss[gloss].definitionTags.push(tag);
+            if (!glossDefinition.definitionTags.find((existingTag) => existingTag.name === tag.name)) {
+                glossDefinition.definitionTags.push(tag);
             }
         }
 
-        if (!appendTo) {
-            // result->expressions[ Expression1[ Reading1[ Tag1, Tag2 ] ], Expression2, ... ]
-            if (!result.expressions.has(definition.expression)) {
-                result.expressions.set(definition.expression, new Map());
+        if (appendTo === null) {
+            /*
+                Data layout:
+                resultExpressionsMap = new Map([
+                    [expression, new Map([
+                        [reading, new Map([
+                            [tagName, tagInfo],
+                            ...
+                        ])],
+                        ...
+                    ])],
+                    ...
+                ]);
+            */
+            let readingMap = resultExpressionsMap.get(expression);
+            if (typeof readingMap === 'undefined') {
+                readingMap = new Map();
+                resultExpressionsMap.set(expression, readingMap);
             }
-            if (!result.expressions.get(definition.expression).has(definition.reading)) {
-                result.expressions.get(definition.expression).set(definition.reading, []);
+
+            let termTagsMap = readingMap.get(reading);
+            if (typeof termTagsMap === 'undefined') {
+                termTagsMap = new Map();
+                readingMap.set(reading, termTagsMap);
             }
 
             for (const tag of definition.termTags) {
-                if (!result.expressions.get(definition.expression).get(definition.reading).find((existingTag) => existingTag.name === tag.name)) {
-                    result.expressions.get(definition.expression).get(definition.reading).push(tag);
+                if (!termTagsMap.has(tag.name)) {
+                    termTagsMap.set(tag.name, tag);
                 }
             }
         }
     }
 
-    for (const gloss in definitionsByGloss) {
-        const definition = definitionsByGloss[gloss];
-        definition.only = [];
-        if (!utilSetEqual(definition.expression, result.expression)) {
-            for (const expression of utilSetIntersection(definition.expression, result.expression)) {
-                definition.only.push(expression);
-            }
+    for (const definition of definitionsByGloss.values()) {
+        const only = [];
+        const expressionSet = definition.expression;
+        const readingSet = definition.reading;
+        if (!dictAreSetsEqual(expressionSet, resultExpressionSet)) {
+            only.push(...dictGetSetIntersection(expressionSet, resultExpressionSet));
         }
-        if (!utilSetEqual(definition.reading, result.reading)) {
-            for (const reading of utilSetIntersection(definition.reading, result.reading)) {
-                definition.only.push(reading);
-            }
+        if (!dictAreSetsEqual(readingSet, resultReadingSet)) {
+            only.push(...dictGetSetIntersection(readingSet, resultReadingSet));
         }
+        definition.only = only;
     }
 
     return definitionsByGloss;
@@ -330,7 +359,7 @@ async function dictFieldFormat(field, definition, mode, options, templates, exce
         }
         data.marker = marker;
         try {
-            return await apiTemplateRender(templates, data, true);
+            return await apiTemplateRender(templates, data);
         } catch (e) {
             if (exceptions) { exceptions.push(e); }
             return `{${marker}-render-error}`;
diff --git a/ext/bg/js/handlebars.js b/ext/bg/js/handlebars.js
index 62f89ee4..b1443447 100644
--- a/ext/bg/js/handlebars.js
+++ b/ext/bg/js/handlebars.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global jpIsCharCodeKanji, jpDistributeFurigana, Handlebars*/
 
 function handlebarsEscape(text) {
     return Handlebars.Utils.escapeExpression(text);
@@ -134,11 +135,6 @@ function handlebarsRegisterHelpers() {
     }
 }
 
-function handlebarsRenderStatic(name, data) {
-    handlebarsRegisterHelpers();
-    return Handlebars.templates[name](data).trim();
-}
-
 function handlebarsRenderDynamic(template, data) {
     handlebarsRegisterHelpers();
     const cache = handlebarsRenderDynamic._cache;
diff --git a/ext/mixed/js/japanese.js b/ext/bg/js/japanese.js
index 0da822d7..abb32da4 100644
--- a/ext/mixed/js/japanese.js
+++ b/ext/bg/js/japanese.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global wanakana*/
 
 const JP_HALFWIDTH_KATAKANA_MAPPING = new Map([
     ['ｦ', 'ヲヺ-'],
@@ -108,7 +109,7 @@ const JP_JAPANESE_RANGES = [
     [0xff1a, 0xff1f], // Fullwidth punctuation 2
     [0xff3b, 0xff3f], // Fullwidth punctuation 3
     [0xff5b, 0xff60], // Fullwidth punctuation 4
-    [0xffe0, 0xffee], // Currency markers
+    [0xffe0, 0xffee]  // Currency markers
 ];
 
 
@@ -223,15 +224,15 @@ function jpDistributeFurigana(expression, reading) {
     }
 
     let isAmbiguous = false;
-    const segmentize = (reading, groups) => {
+    const segmentize = (reading2, groups) => {
         if (groups.length === 0 || isAmbiguous) {
             return [];
         }
 
         const group = groups[0];
         if (group.mode === 'kana') {
-            if (jpKatakanaToHiragana(reading).startsWith(jpKatakanaToHiragana(group.text))) {
-                const readingLeft = reading.substring(group.text.length);
+            if (jpKatakanaToHiragana(reading2).startsWith(jpKatakanaToHiragana(group.text))) {
+                const readingLeft = reading2.substring(group.text.length);
                 const segs = segmentize(readingLeft, groups.splice(1));
                 if (segs) {
                     return [{text: group.text}].concat(segs);
@@ -239,9 +240,9 @@ function jpDistributeFurigana(expression, reading) {
             }
         } else {
             let foundSegments = null;
-            for (let i = reading.length; i >= group.text.length; --i) {
-                const readingUsed = reading.substring(0, i);
-                const readingLeft = reading.substring(i);
+            for (let i = reading2.length; i >= group.text.length; --i) {
+                const readingUsed = reading2.substring(0, i);
+                const readingLeft = reading2.substring(i);
                 const segs = segmentize(readingLeft, groups.slice(1));
                 if (segs) {
                     if (foundSegments !== null) {
diff --git a/ext/bg/js/json-schema.js b/ext/bg/js/json-schema.js
index 5d596a8b..58f804fd 100644
--- a/ext/bg/js/json-schema.js
+++ b/ext/bg/js/json-schema.js
@@ -64,7 +64,7 @@ class JsonSchemaProxyHandler {
             }
         }
 
-        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property);
+        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property, target);
         if (propertySchema === null) {
             return;
         }
@@ -86,17 +86,14 @@ class JsonSchemaProxyHandler {
             }
         }
 
-        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property);
+        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property, target);
         if (propertySchema === null) {
             throw new Error(`Property ${property} not supported`);
         }
 
         value = JsonSchema.isolate(value);
 
-        const error = JsonSchemaProxyHandler.validate(value, propertySchema);
-        if (error !== null) {
-            throw new Error(`Invalid value: ${error}`);
-        }
+        JsonSchemaProxyHandler.validate(value, propertySchema, new JsonSchemaTraversalInfo(value, propertySchema));
 
         target[property] = value;
         return true;
@@ -122,151 +119,329 @@ class JsonSchemaProxyHandler {
         throw new Error('construct not supported');
     }
 
-    static getPropertySchema(schema, property) {
-        const type = schema.type;
-        if (Array.isArray(type)) {
-            throw new Error(`Ambiguous property type for ${property}`);
-        }
+    static getPropertySchema(schema, property, value, path=null) {
+        const type = JsonSchemaProxyHandler.getSchemaOrValueType(schema, value);
         switch (type) {
             case 'object':
             {
                 const properties = schema.properties;
-                if (properties !== null && typeof properties === 'object' && !Array.isArray(properties)) {
-                    if (Object.prototype.hasOwnProperty.call(properties, property)) {
-                        return properties[property];
+                if (JsonSchemaProxyHandler.isObject(properties)) {
+                    const propertySchema = properties[property];
+                    if (JsonSchemaProxyHandler.isObject(propertySchema)) {
+                        if (path !== null) { path.push(['properties', properties], [property, propertySchema]); }
+                        return propertySchema;
                     }
                 }
 
                 const additionalProperties = schema.additionalProperties;
-                return (additionalProperties !== null && typeof additionalProperties === 'object' && !Array.isArray(additionalProperties)) ? additionalProperties : null;
+                if (additionalProperties === false) {
+                    return null;
+                } else if (JsonSchemaProxyHandler.isObject(additionalProperties)) {
+                    if (path !== null) { path.push(['additionalProperties', additionalProperties]); }
+                    return additionalProperties;
+                } else {
+                    const result = JsonSchemaProxyHandler._unconstrainedSchema;
+                    if (path !== null) { path.push([null, result]); }
+                    return result;
+                }
             }
             case 'array':
             {
                 const items = schema.items;
-                return (items !== null && typeof items === 'object' && !Array.isArray(items)) ? items : null;
+                if (JsonSchemaProxyHandler.isObject(items)) {
+                    return items;
+                }
+                if (Array.isArray(items)) {
+                    if (property >= 0 && property < items.length) {
+                        const propertySchema = items[property];
+                        if (JsonSchemaProxyHandler.isObject(propertySchema)) {
+                            if (path !== null) { path.push(['items', items], [property, propertySchema]); }
+                            return propertySchema;
+                        }
+                    }
+                }
+
+                const additionalItems = schema.additionalItems;
+                if (additionalItems === false) {
+                    return null;
+                } else if (JsonSchemaProxyHandler.isObject(additionalItems)) {
+                    if (path !== null) { path.push(['additionalItems', additionalItems]); }
+                    return additionalItems;
+                } else {
+                    const result = JsonSchemaProxyHandler._unconstrainedSchema;
+                    if (path !== null) { path.push([null, result]); }
+                    return result;
+                }
             }
             default:
                 return null;
         }
     }
 
-    static validate(value, schema) {
+    static getSchemaOrValueType(schema, value) {
+        const type = schema.type;
+
+        if (Array.isArray(type)) {
+            if (typeof value !== 'undefined') {
+                const valueType = JsonSchemaProxyHandler.getValueType(value);
+                if (type.indexOf(valueType) >= 0) {
+                    return valueType;
+                }
+            }
+            return null;
+        }
+
+        if (typeof type === 'undefined') {
+            if (typeof value !== 'undefined') {
+                return JsonSchemaProxyHandler.getValueType(value);
+            }
+            return null;
+        }
+
+        return type;
+    }
+
+    static validate(value, schema, info) {
+        JsonSchemaProxyHandler.validateSingleSchema(value, schema, info);
+        JsonSchemaProxyHandler.validateConditional(value, schema, info);
+        JsonSchemaProxyHandler.validateAllOf(value, schema, info);
+        JsonSchemaProxyHandler.validateAnyOf(value, schema, info);
+        JsonSchemaProxyHandler.validateOneOf(value, schema, info);
+        JsonSchemaProxyHandler.validateNoneOf(value, schema, info);
+    }
+
+    static validateConditional(value, schema, info) {
+        const ifSchema = schema.if;
+        if (!JsonSchemaProxyHandler.isObject(ifSchema)) { return; }
+
+        let okay = true;
+        info.schemaPush('if', ifSchema);
+        try {
+            JsonSchemaProxyHandler.validate(value, ifSchema, info);
+        } catch (e) {
+            okay = false;
+        }
+        info.schemaPop();
+
+        const nextSchema = okay ? schema.then : schema.else;
+        if (JsonSchemaProxyHandler.isObject(nextSchema)) {
+            info.schemaPush(okay ? 'then' : 'else', nextSchema);
+            JsonSchemaProxyHandler.validate(value, nextSchema, info);
+            info.schemaPop();
+        }
+    }
+
+    static validateAllOf(value, schema, info) {
+        const subSchemas = schema.allOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('allOf', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            JsonSchemaProxyHandler.validate(value, subSchema, info);
+            info.schemaPop();
+        }
+        info.schemaPop();
+    }
+
+    static validateAnyOf(value, schema, info) {
+        const subSchemas = schema.anyOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('anyOf', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+                return;
+            } catch (e) {
+                // NOP
+            }
+            info.schemaPop();
+        }
+
+        throw new JsonSchemaValidationError('0 anyOf schemas matched', value, schema, info);
+        // info.schemaPop(); // Unreachable
+    }
+
+    static validateOneOf(value, schema, info) {
+        const subSchemas = schema.oneOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('oneOf', subSchemas);
+        let count = 0;
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+                ++count;
+            } catch (e) {
+                // NOP
+            }
+            info.schemaPop();
+        }
+
+        if (count !== 1) {
+            throw new JsonSchemaValidationError(`${count} oneOf schemas matched`, value, schema, info);
+        }
+
+        info.schemaPop();
+    }
+
+    static validateNoneOf(value, schema, info) {
+        const subSchemas = schema.not;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('not', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+            } catch (e) {
+                info.schemaPop();
+                continue;
+            }
+            throw new JsonSchemaValidationError(`not[${i}] schema matched`, value, schema, info);
+        }
+        info.schemaPop();
+    }
+
+    static validateSingleSchema(value, schema, info) {
         const type = JsonSchemaProxyHandler.getValueType(value);
         const schemaType = schema.type;
         if (!JsonSchemaProxyHandler.isValueTypeAny(value, type, schemaType)) {
-            return `Value type ${type} does not match schema type ${schemaType}`;
+            throw new JsonSchemaValidationError(`Value type ${type} does not match schema type ${schemaType}`, value, schema, info);
         }
 
         const schemaEnum = schema.enum;
         if (Array.isArray(schemaEnum) && !JsonSchemaProxyHandler.valuesAreEqualAny(value, schemaEnum)) {
-            return 'Invalid enum value';
+            throw new JsonSchemaValidationError('Invalid enum value', value, schema, info);
         }
 
         switch (type) {
             case 'number':
-                return JsonSchemaProxyHandler.validateNumber(value, schema);
+                JsonSchemaProxyHandler.validateNumber(value, schema, info);
+                break;
             case 'string':
-                return JsonSchemaProxyHandler.validateString(value, schema);
+                JsonSchemaProxyHandler.validateString(value, schema, info);
+                break;
             case 'array':
-                return JsonSchemaProxyHandler.validateArray(value, schema);
+                JsonSchemaProxyHandler.validateArray(value, schema, info);
+                break;
             case 'object':
-                return JsonSchemaProxyHandler.validateObject(value, schema);
-            default:
-                return null;
+                JsonSchemaProxyHandler.validateObject(value, schema, info);
+                break;
         }
     }
 
-    static validateNumber(value, schema) {
+    static validateNumber(value, schema, info) {
         const multipleOf = schema.multipleOf;
         if (typeof multipleOf === 'number' && Math.floor(value / multipleOf) * multipleOf !== value) {
-            return `Number is not a multiple of ${multipleOf}`;
+            throw new JsonSchemaValidationError(`Number is not a multiple of ${multipleOf}`, value, schema, info);
         }
 
         const minimum = schema.minimum;
         if (typeof minimum === 'number' && value < minimum) {
-            return `Number is less than ${minimum}`;
+            throw new JsonSchemaValidationError(`Number is less than ${minimum}`, value, schema, info);
         }
 
         const exclusiveMinimum = schema.exclusiveMinimum;
         if (typeof exclusiveMinimum === 'number' && value <= exclusiveMinimum) {
-            return `Number is less than or equal to ${exclusiveMinimum}`;
+            throw new JsonSchemaValidationError(`Number is less than or equal to ${exclusiveMinimum}`, value, schema, info);
         }
 
         const maximum = schema.maximum;
         if (typeof maximum === 'number' && value > maximum) {
-            return `Number is greater than ${maximum}`;
+            throw new JsonSchemaValidationError(`Number is greater than ${maximum}`, value, schema, info);
         }
 
         const exclusiveMaximum = schema.exclusiveMaximum;
         if (typeof exclusiveMaximum === 'number' && value >= exclusiveMaximum) {
-            return `Number is greater than or equal to ${exclusiveMaximum}`;
+            throw new JsonSchemaValidationError(`Number is greater than or equal to ${exclusiveMaximum}`, value, schema, info);
         }
-
-        return null;
     }
 
-    static validateString(value, schema) {
+    static validateString(value, schema, info) {
         const minLength = schema.minLength;
         if (typeof minLength === 'number' && value.length < minLength) {
-            return 'String length too short';
+            throw new JsonSchemaValidationError('String length too short', value, schema, info);
         }
 
-        const maxLength = schema.minLength;
+        const maxLength = schema.maxLength;
         if (typeof maxLength === 'number' && value.length > maxLength) {
-            return 'String length too long';
+            throw new JsonSchemaValidationError('String length too long', value, schema, info);
         }
-
-        return null;
     }
 
-    static validateArray(value, schema) {
+    static validateArray(value, schema, info) {
         const minItems = schema.minItems;
         if (typeof minItems === 'number' && value.length < minItems) {
-            return 'Array length too short';
+            throw new JsonSchemaValidationError('Array length too short', value, schema, info);
         }
 
         const maxItems = schema.maxItems;
         if (typeof maxItems === 'number' && value.length > maxItems) {
-            return 'Array length too long';
+            throw new JsonSchemaValidationError('Array length too long', value, schema, info);
         }
 
-        return null;
+        for (let i = 0, ii = value.length; i < ii; ++i) {
+            const schemaPath = [];
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i, value, schemaPath);
+            if (propertySchema === null) {
+                throw new JsonSchemaValidationError(`No schema found for array[${i}]`, value, schema, info);
+            }
+
+            const propertyValue = value[i];
+
+            for (const [p, s] of schemaPath) { info.schemaPush(p, s); }
+            info.valuePush(i, propertyValue);
+            JsonSchemaProxyHandler.validate(propertyValue, propertySchema, info);
+            info.valuePop();
+            for (let j = 0, jj = schemaPath.length; j < jj; ++j) { info.schemaPop(); }
+        }
     }
 
-    static validateObject(value, schema) {
+    static validateObject(value, schema, info) {
         const properties = new Set(Object.getOwnPropertyNames(value));
 
         const required = schema.required;
         if (Array.isArray(required)) {
             for (const property of required) {
                 if (!properties.has(property)) {
-                    return `Missing property ${property}`;
+                    throw new JsonSchemaValidationError(`Missing property ${property}`, value, schema, info);
                 }
             }
         }
 
         const minProperties = schema.minProperties;
         if (typeof minProperties === 'number' && properties.length < minProperties) {
-            return 'Not enough object properties';
+            throw new JsonSchemaValidationError('Not enough object properties', value, schema, info);
         }
 
         const maxProperties = schema.maxProperties;
         if (typeof maxProperties === 'number' && properties.length > maxProperties) {
-            return 'Too many object properties';
+            throw new JsonSchemaValidationError('Too many object properties', value, schema, info);
         }
 
         for (const property of properties) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+            const schemaPath = [];
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value, schemaPath);
             if (propertySchema === null) {
-                return `No schema found for ${property}`;
-            }
-            const error = JsonSchemaProxyHandler.validate(value[property], propertySchema);
-            if (error !== null) {
-                return error;
+                throw new JsonSchemaValidationError(`No schema found for ${property}`, value, schema, info);
             }
-        }
 
-        return null;
+            const propertyValue = value[property];
+
+            for (const [p, s] of schemaPath) { info.schemaPush(p, s); }
+            info.valuePush(property, propertyValue);
+            JsonSchemaProxyHandler.validate(propertyValue, propertySchema, info);
+            info.valuePop();
+            for (let i = 0; i < schemaPath.length; ++i) { info.schemaPop(); }
+        }
     }
 
     static isValueTypeAny(value, type, schemaTypes) {
@@ -372,14 +547,14 @@ class JsonSchemaProxyHandler {
             for (const property of required) {
                 properties.delete(property);
 
-                const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+                const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value);
                 if (propertySchema === null) { continue; }
                 value[property] = JsonSchemaProxyHandler.getValidValueOrDefault(propertySchema, value[property]);
             }
         }
 
         for (const property of properties) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value);
             if (propertySchema === null) {
                 Reflect.deleteProperty(value, property);
             } else {
@@ -392,13 +567,53 @@ class JsonSchemaProxyHandler {
 
     static populateArrayDefaults(value, schema) {
         for (let i = 0, ii = value.length; i < ii; ++i) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i);
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i, value);
             if (propertySchema === null) { continue; }
             value[i] = JsonSchemaProxyHandler.getValidValueOrDefault(propertySchema, value[i]);
         }
 
         return value;
     }
+
+    static isObject(value) {
+        return typeof value === 'object' && value !== null && !Array.isArray(value);
+    }
+}
+
+JsonSchemaProxyHandler._unconstrainedSchema = {};
+
+class JsonSchemaTraversalInfo {
+    constructor(value, schema) {
+        this.valuePath = [];
+        this.schemaPath = [];
+        this.valuePush(null, value);
+        this.schemaPush(null, schema);
+    }
+
+    valuePush(path, value) {
+        this.valuePath.push([path, value]);
+    }
+
+    valuePop() {
+        this.valuePath.pop();
+    }
+
+    schemaPush(path, schema) {
+        this.schemaPath.push([path, schema]);
+    }
+
+    schemaPop() {
+        this.schemaPath.pop();
+    }
+}
+
+class JsonSchemaValidationError extends Error {
+    constructor(message, value, schema, info) {
+        super(message);
+        this.value = value;
+        this.schema = schema;
+        this.info = info;
+    }
 }
 
 class JsonSchema {
@@ -406,6 +621,10 @@ class JsonSchema {
         return new Proxy(target, new JsonSchemaProxyHandler(schema));
     }
 
+    static validate(value, schema) {
+        return JsonSchemaProxyHandler.validate(value, schema, new JsonSchemaTraversalInfo(value, schema));
+    }
+
     static getValidValueOrDefault(schema, value) {
         return JsonSchemaProxyHandler.getValidValueOrDefault(schema, value);
     }
diff --git a/ext/bg/js/options.js b/ext/bg/js/options.js
index d93862bf..f9db99a2 100644
--- a/ext/bg/js/options.js
+++ b/ext/bg/js/options.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global utilStringHashCode*/
 
 /*
  * Generic options functions
@@ -266,6 +267,7 @@ function profileOptionsCreateDefaults() {
     return {
         general: {
             enable: true,
+            enableClipboardPopups: false,
             resultOutputMode: 'group',
             debugInfo: false,
             maxResults: 32,
@@ -316,7 +318,8 @@ function profileOptionsCreateDefaults() {
             popupNestingMaxDepth: 0,
             enablePopupSearch: false,
             enableOnPopupExpressions: false,
-            enableOnSearchPage: true
+            enableOnSearchPage: true,
+            enableSearchTags: false
         },
 
         translation: {
diff --git a/ext/bg/js/page-exit-prevention.js b/ext/bg/js/page-exit-prevention.js
index 3a320db3..be06c495 100644
--- a/ext/bg/js/page-exit-prevention.js
+++ b/ext/bg/js/page-exit-prevention.js
@@ -18,43 +18,43 @@
 
 
 class PageExitPrevention {
-  constructor() {
-  }
-
-  start() {
-      PageExitPrevention._addInstance(this);
-  }
-
-  end() {
-      PageExitPrevention._removeInstance(this);
-  }
-
-  static _addInstance(instance) {
-      const size = PageExitPrevention._instances.size;
-      PageExitPrevention._instances.set(instance, true);
-      if (size === 0) {
-          window.addEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
-      }
-  }
-
-  static _removeInstance(instance) {
-      if (
-          PageExitPrevention._instances.delete(instance) &&
-          PageExitPrevention._instances.size === 0
-      ) {
-          window.removeEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
-      }
-  }
-
-  static _onBeforeUnload(e) {
-      if (PageExitPrevention._instances.size === 0) {
-          return;
-      }
-
-      e.preventDefault();
-      e.returnValue = '';
-      return '';
-  }
+    constructor() {
+    }
+
+    start() {
+        PageExitPrevention._addInstance(this);
+    }
+
+    end() {
+        PageExitPrevention._removeInstance(this);
+    }
+
+    static _addInstance(instance) {
+        const size = PageExitPrevention._instances.size;
+        PageExitPrevention._instances.set(instance, true);
+        if (size === 0) {
+            window.addEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
+        }
+    }
+
+    static _removeInstance(instance) {
+        if (
+            PageExitPrevention._instances.delete(instance) &&
+            PageExitPrevention._instances.size === 0
+        ) {
+            window.removeEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
+        }
+    }
+
+    static _onBeforeUnload(e) {
+        if (PageExitPrevention._instances.size === 0) {
+            return;
+        }
+
+        e.preventDefault();
+        e.returnValue = '';
+        return '';
+    }
 }
 
 PageExitPrevention._instances = new Map();
diff --git a/ext/bg/js/search-frontend.js b/ext/bg/js/search-frontend.js
index e453ccef..509c4009 100644
--- a/ext/bg/js/search-frontend.js
+++ b/ext/bg/js/search-frontend.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGet*/
 
 async function searchFrontendSetup() {
     const optionsContext = {
diff --git a/ext/bg/js/search-query-parser-generator.js b/ext/bg/js/search-query-parser-generator.js
new file mode 100644
index 00000000..1ab23a82
--- /dev/null
+++ b/ext/bg/js/search-query-parser-generator.js
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*global apiGetQueryParserTemplatesHtml, TemplateHandler*/
+
+class QueryParserGenerator {
+    constructor() {
+        this._templateHandler = null;
+    }
+
+    async prepare() {
+        const html = await apiGetQueryParserTemplatesHtml();
+        this._templateHandler = new TemplateHandler(html);
+    }
+
+    createParseResult(terms, preview=false) {
+        const fragment = document.createDocumentFragment();
+        for (const term of terms) {
+            const termContainer = this._templateHandler.instantiate(preview ? 'term-preview' : 'term');
+            for (const segment of term) {
+                if (!segment.text.trim()) { continue; }
+                if (!segment.reading || !segment.reading.trim()) {
+                    termContainer.appendChild(this.createSegmentText(segment.text));
+                } else {
+                    termContainer.appendChild(this.createSegment(segment));
+                }
+            }
+            fragment.appendChild(termContainer);
+        }
+        return fragment;
+    }
+
+    createSegment(segment) {
+        const segmentContainer = this._templateHandler.instantiate('segment');
+        const segmentTextContainer = segmentContainer.querySelector('.query-parser-segment-text');
+        const segmentReadingContainer = segmentContainer.querySelector('.query-parser-segment-reading');
+        segmentTextContainer.appendChild(this.createSegmentText(segment.text));
+        segmentReadingContainer.textContent = segment.reading;
+        return segmentContainer;
+    }
+
+    createSegmentText(text) {
+        const fragment = document.createDocumentFragment();
+        for (const chr of text) {
+            const charContainer = this._templateHandler.instantiate('char');
+            charContainer.textContent = chr;
+            fragment.appendChild(charContainer);
+        }
+        return fragment;
+    }
+
+    createParserSelect(parseResults, selectedParser) {
+        const selectContainer = this._templateHandler.instantiate('select');
+        for (const parseResult of parseResults) {
+            const optionContainer = this._templateHandler.instantiate('select-option');
+            optionContainer.value = parseResult.id;
+            optionContainer.textContent = parseResult.name;
+            optionContainer.defaultSelected = selectedParser === parseResult.id;
+            selectContainer.appendChild(optionContainer);
+        }
+        return selectContainer;
+    }
+}
diff --git a/ext/bg/js/search-query-parser.js b/ext/bg/js/search-query-parser.js
index e8e6d11f..0d4aaa50 100644
--- a/ext/bg/js/search-query-parser.js
+++ b/ext/bg/js/search-query-parser.js
@@ -16,17 +16,24 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiTermsFind, apiOptionsSet, apiTextParse, apiTextParseMecab, TextScanner, QueryParserGenerator*/
 
 class QueryParser extends TextScanner {
     constructor(search) {
-        super(document.querySelector('#query-parser'), [], [], []);
+        super(document.querySelector('#query-parser-content'), [], [], []);
         this.search = search;
 
         this.parseResults = [];
         this.selectedParser = null;
 
-        this.queryParser = document.querySelector('#query-parser');
-        this.queryParserSelect = document.querySelector('#query-parser-select');
+        this.queryParser = document.querySelector('#query-parser-content');
+        this.queryParserSelect = document.querySelector('#query-parser-select-container');
+
+        this.queryParserGenerator = new QueryParserGenerator();
+    }
+
+    async prepare() {
+        await this.queryParserGenerator.prepare();
     }
 
     onError(error) {
@@ -52,7 +59,7 @@ class QueryParser extends TextScanner {
 
         this.search.setContent('terms', {definitions, context: {
             focus: false,
-            disableHistory: cause === 'mouse' ? true : false,
+            disableHistory: cause === 'mouse',
             sentence: {text: searchText, offset: 0},
             url: window.location.href
         }});
@@ -64,7 +71,7 @@ class QueryParser extends TextScanner {
         const selectedParser = e.target.value;
         this.selectedParser = selectedParser;
         apiOptionsSet({parsing: {selectedParser}}, this.search.getOptionsContext());
-        this.renderParseResult(this.getParseResult());
+        this.renderParseResult();
     }
 
     getMouseEventListeners() {
@@ -113,13 +120,13 @@ class QueryParser extends TextScanner {
     async setText(text) {
         this.search.setSpinnerVisible(true);
 
-        await this.setPreview(text);
+        this.setPreview(text);
 
         this.parseResults = await this.parseText(text);
         this.refreshSelectedParser();
 
         this.renderParserSelect();
-        await this.renderParseResult();
+        this.renderParseResult();
 
         this.search.setSpinnerVisible(false);
     }
@@ -146,57 +153,29 @@ class QueryParser extends TextScanner {
         return results;
     }
 
-    async setPreview(text) {
+    setPreview(text) {
         const previewTerms = [];
         for (let i = 0, ii = text.length; i < ii; i += 2) {
             const tempText = text.substring(i, i + 2);
-            previewTerms.push([{text: tempText.split('')}]);
+            previewTerms.push([{text: tempText}]);
         }
-        this.queryParser.innerHTML = await apiTemplateRender('query-parser.html', {
-            terms: previewTerms,
-            preview: true
-        });
+        this.queryParser.textContent = '';
+        this.queryParser.appendChild(this.queryParserGenerator.createParseResult(previewTerms, true));
     }
 
     renderParserSelect() {
-        this.queryParserSelect.innerHTML = '';
+        this.queryParserSelect.textContent = '';
         if (this.parseResults.length > 1) {
-            const select = document.createElement('select');
-            select.classList.add('form-control');
-            for (const parseResult of this.parseResults) {
-                const option = document.createElement('option');
-                option.value = parseResult.id;
-                option.innerText = parseResult.name;
-                option.defaultSelected = this.selectedParser === parseResult.id;
-                select.appendChild(option);
-            }
+            const select = this.queryParserGenerator.createParserSelect(this.parseResults, this.selectedParser);
             select.addEventListener('change', this.onParserChange.bind(this));
             this.queryParserSelect.appendChild(select);
         }
     }
 
-    async renderParseResult() {
+    renderParseResult() {
         const parseResult = this.getParseResult();
-        if (!parseResult) {
-            this.queryParser.innerHTML = '';
-            return;
-        }
-
-        this.queryParser.innerHTML = await apiTemplateRender(
-            'query-parser.html',
-            {terms: QueryParser.processParseResultForDisplay(parseResult.parsedText)}
-        );
-    }
-
-    static processParseResultForDisplay(result) {
-        return result.map((term) => {
-            return term.filter((part) => part.text.trim()).map((part) => {
-                return {
-                    text: part.text.split(''),
-                    reading: part.reading,
-                    raw: !part.reading || !part.reading.trim()
-                };
-            });
-        });
+        this.queryParser.textContent = '';
+        if (!parseResult) { return; }
+        this.queryParser.appendChild(this.queryParserGenerator.createParseResult(parseResult.parsedText));
     }
 }
diff --git a/ext/bg/js/search.js b/ext/bg/js/search.js
index f5c641a8..98e167ad 100644
--- a/ext/bg/js/search.js
+++ b/ext/bg/js/search.js
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsSet, apiTermsFind, Display, QueryParser, ClipboardMonitor*/
+
 class DisplaySearch extends Display {
     constructor() {
         super(document.querySelector('#spinner'), document.querySelector('#content'));
@@ -36,12 +38,7 @@ class DisplaySearch extends Display {
         this.introVisible = true;
         this.introAnimationTimer = null;
 
-        this.isFirefox = false;
-
-        this.clipboardMonitorTimerId = null;
-        this.clipboardMonitorTimerToken = null;
-        this.clipboardInterval = 250;
-        this.clipboardPreviousText = null;
+        this.clipboardMonitor = new ClipboardMonitor();
     }
 
     static create() {
@@ -52,13 +49,17 @@ class DisplaySearch extends Display {
 
     async prepare() {
         try {
-            await this.initialize();
-            this.isFirefox = await DisplaySearch._isFirefox();
+            const superPromise = super.prepare();
+            const queryParserPromise = this.queryParser.prepare();
+            await Promise.all([superPromise, queryParserPromise]);
+
+            const {queryParams: {query='', mode=''}} = parseUrl(window.location.href);
 
             if (this.search !== null) {
                 this.search.addEventListener('click', (e) => this.onSearch(e), false);
             }
             if (this.query !== null) {
+                document.documentElement.dataset.searchMode = mode;
                 this.query.addEventListener('input', () => this.onSearchInput(), false);
 
                 if (this.wanakanaEnable !== null) {
@@ -69,34 +70,26 @@ class DisplaySearch extends Display {
                         this.wanakanaEnable.checked = false;
                     }
                     this.wanakanaEnable.addEventListener('change', (e) => {
-                        const query = DisplaySearch.getSearchQueryFromLocation(window.location.href) || '';
+                        const {queryParams: {query: query2=''}} = parseUrl(window.location.href);
                         if (e.target.checked) {
                             window.wanakana.bind(this.query);
-                            this.setQuery(window.wanakana.toKana(query));
                             apiOptionsSet({general: {enableWanakana: true}}, this.getOptionsContext());
                         } else {
                             window.wanakana.unbind(this.query);
-                            this.setQuery(query);
                             apiOptionsSet({general: {enableWanakana: false}}, this.getOptionsContext());
                         }
+                        this.setQuery(query2);
                         this.onSearchQueryUpdated(this.query.value, false);
                     });
                 }
 
-                const query = DisplaySearch.getSearchQueryFromLocation(window.location.href);
-                if (query !== null) {
-                    if (this.isWanakanaEnabled()) {
-                        this.setQuery(window.wanakana.toKana(query));
-                    } else {
-                        this.setQuery(query);
-                    }
-                    this.onSearchQueryUpdated(this.query.value, false);
-                }
+                this.setQuery(query);
+                this.onSearchQueryUpdated(this.query.value, false);
             }
-            if (this.clipboardMonitorEnable !== null) {
+            if (this.clipboardMonitorEnable !== null && mode !== 'popup') {
                 if (this.options.general.enableClipboardMonitor === true) {
                     this.clipboardMonitorEnable.checked = true;
-                    this.startClipboardMonitor();
+                    this.clipboardMonitor.start();
                 } else {
                     this.clipboardMonitorEnable.checked = false;
                 }
@@ -106,7 +99,7 @@ class DisplaySearch extends Display {
                             {permissions: ['clipboardRead']},
                             (granted) => {
                                 if (granted) {
-                                    this.startClipboardMonitor();
+                                    this.clipboardMonitor.start();
                                     apiOptionsSet({general: {enableClipboardMonitor: true}}, this.getOptionsContext());
                                 } else {
                                     e.target.checked = false;
@@ -114,16 +107,20 @@ class DisplaySearch extends Display {
                             }
                         );
                     } else {
-                        this.stopClipboardMonitor();
+                        this.clipboardMonitor.stop();
                         apiOptionsSet({general: {enableClipboardMonitor: false}}, this.getOptionsContext());
                     }
                 });
             }
 
+            chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
+
             window.addEventListener('popstate', (e) => this.onPopState(e));
+            window.addEventListener('copy', (e) => this.onCopy(e));
+
+            this.clipboardMonitor.onClipboardText = (text) => this.onExternalSearchUpdate(text);
 
             this.updateSearchButton();
-            this.initClipboardMonitor();
         } catch (e) {
             this.onError(e);
         }
@@ -159,25 +156,32 @@ class DisplaySearch extends Display {
         e.preventDefault();
 
         const query = this.query.value;
+
         this.queryParser.setText(query);
-        const queryString = query.length > 0 ? `?query=${encodeURIComponent(query)}` : '';
-        window.history.pushState(null, '', `${window.location.pathname}${queryString}`);
+
+        const url = new URL(window.location.href);
+        url.searchParams.set('query', query);
+        window.history.pushState(null, '', url.toString());
+
         this.onSearchQueryUpdated(query, true);
     }
 
     onPopState() {
-        const query = DisplaySearch.getSearchQueryFromLocation(window.location.href) || '';
-        if (this.query !== null) {
-            if (this.isWanakanaEnabled()) {
-                this.setQuery(window.wanakana.toKana(query));
-            } else {
-                this.setQuery(query);
-            }
-        }
-
+        const {queryParams: {query='', mode=''}} = parseUrl(window.location.href);
+        document.documentElement.dataset.searchMode = mode;
+        this.setQuery(query);
         this.onSearchQueryUpdated(this.query.value, false);
     }
 
+    onRuntimeMessage({action, params}, sender, callback) {
+        const handler = DisplaySearch._runtimeMessageHandlers.get(action);
+        if (typeof handler !== 'function') { return false; }
+
+        const result = handler(this, params, sender);
+        callback(result);
+        return false;
+    }
+
     onKeyDown(e) {
         const key = Display.getKeyFromEvent(e);
         const ignoreKeys = DisplaySearch.onKeyDownIgnoreKeys;
@@ -202,6 +206,19 @@ class DisplaySearch extends Display {
         }
     }
 
+    onCopy() {
+        // ignore copy from search page
+        this.clipboardMonitor.setPreviousText(document.getSelection().toString().trim());
+    }
+
+    onExternalSearchUpdate(text) {
+        this.setQuery(text);
+        const url = new URL(window.location.href);
+        url.searchParams.set('query', text);
+        window.history.pushState(null, '', url.toString());
+        this.onSearchQueryUpdated(this.query.value, true);
+    }
+
     async onSearchQueryUpdated(query, animate) {
         try {
             const details = {};
@@ -241,74 +258,6 @@ class DisplaySearch extends Display {
         this.queryParser.setOptions(this.options);
     }
 
-    initClipboardMonitor() {
-        // ignore copy from search page
-        window.addEventListener('copy', () => {
-            this.clipboardPreviousText = document.getSelection().toString().trim();
-        });
-    }
-
-    startClipboardMonitor() {
-        // The token below is used as a unique identifier to ensure that a new clipboard monitor
-        // hasn't been started during the await call. The check below the await this.getClipboardText()
-        // call will exit early if the reference has changed.
-        const token = {};
-        const intervalCallback = async () => {
-            this.clipboardMonitorTimerId = null;
-
-            let text = await this.getClipboardText();
-            if (this.clipboardMonitorTimerToken !== token) { return; }
-
-            if (
-                typeof text === 'string' &&
-                (text = text.trim()).length > 0 &&
-                text !== this.clipboardPreviousText
-            ) {
-                this.clipboardPreviousText = text;
-                if (jpIsStringPartiallyJapanese(text)) {
-                    this.setQuery(this.isWanakanaEnabled() ? window.wanakana.toKana(text) : text);
-                    window.history.pushState(null, '', `${window.location.pathname}?query=${encodeURIComponent(text)}`);
-                    this.onSearchQueryUpdated(this.query.value, true);
-                }
-            }
-
-            this.clipboardMonitorTimerId = setTimeout(intervalCallback, this.clipboardInterval);
-        };
-
-        this.clipboardMonitorTimerToken = token;
-
-        intervalCallback();
-    }
-
-    stopClipboardMonitor() {
-        this.clipboardMonitorTimerToken = null;
-        if (this.clipboardMonitorTimerId !== null) {
-            clearTimeout(this.clipboardMonitorTimerId);
-            this.clipboardMonitorTimerId = null;
-        }
-    }
-
-    async getClipboardText() {
-        /*
-        Notes:
-            apiClipboardGet doesn't work on Firefox because document.execCommand('paste')
-            results in an empty string on the web extension background page.
-            This may be a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985
-            Therefore, navigator.clipboard.readText() is used on Firefox.
-
-            navigator.clipboard.readText() can't be used in Chrome for two reasons:
-            * Requires page to be focused, else it rejects with an exception.
-            * When the page is focused, Chrome will request clipboard permission, despite already
-              being an extension with clipboard permissions. It effectively asks for the
-              non-extension permission for clipboard access.
-        */
-        try {
-            return this.isFirefox ? await navigator.clipboard.readText() : await apiClipboardGet();
-        } catch (e) {
-            return null;
-        }
-    }
-
     isWanakanaEnabled() {
         return this.wanakanaEnable !== null && this.wanakanaEnable.checked;
     }
@@ -318,8 +267,9 @@ class DisplaySearch extends Display {
     }
 
     setQuery(query) {
-        this.query.value = query;
-        this.queryParser.setText(query);
+        const interpretedQuery = this.isWanakanaEnabled() ? window.wanakana.toKana(query) : query;
+        this.query.value = interpretedQuery;
+        this.queryParser.setText(interpretedQuery);
     }
 
     setIntroVisible(visible, animate) {
@@ -394,22 +344,6 @@ class DisplaySearch extends Display {
             document.title = `${text} - Yomichan Search`;
         }
     }
-
-    static getSearchQueryFromLocation(url) {
-        const match = /^[^?#]*\?(?:[^&#]*&)?query=([^&#]*)/.exec(url);
-        return match !== null ? decodeURIComponent(match[1]) : null;
-    }
-
-    static async _isFirefox() {
-        const {browser} = await apiGetEnvironmentInfo();
-        switch (browser) {
-            case 'firefox':
-            case 'firefox-mobile':
-                return true;
-            default:
-                return false;
-        }
-    }
 }
 
 DisplaySearch.onKeyDownIgnoreKeys = {
@@ -427,4 +361,8 @@ DisplaySearch.onKeyDownIgnoreKeys = {
     'Shift': []
 };
 
+DisplaySearch._runtimeMessageHandlers = new Map([
+    ['searchQueryUpdate', (self, {query}) => { self.onExternalSearchUpdate(query); }]
+]);
+
 DisplaySearch.instance = DisplaySearch.create();
diff --git a/ext/bg/js/settings/anki-templates.js b/ext/bg/js/settings/anki-templates.js
index 5e74358f..2e80e334 100644
--- a/ext/bg/js/settings/anki-templates.js
+++ b/ext/bg/js/settings/anki-templates.js
@@ -16,6 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+profileOptionsGetDefaultFieldTemplates, ankiGetFieldMarkers, ankiGetFieldMarkersHtml, dictFieldFormat
+apiOptionsGet, apiTermsFind*/
 
 function onAnkiFieldTemplatesReset(e) {
     e.preventDefault();
diff --git a/ext/bg/js/settings/anki.js b/ext/bg/js/settings/anki.js
index 9adb2f2a..4263fc51 100644
--- a/ext/bg/js/settings/anki.js
+++ b/ext/bg/js/settings/anki.js
@@ -16,6 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+utilBackgroundIsolate, utilAnkiGetDeckNames, utilAnkiGetModelNames, utilAnkiGetModelFieldNames
+onFormOptionsChanged*/
 
 // Private
 
@@ -33,14 +36,27 @@ function _ankiSpinnerShow(show) {
 
 function _ankiSetError(error) {
     const node = document.querySelector('#anki-error');
-    if (!node) { return; }
+    const node2 = document.querySelector('#anki-invalid-response-error');
     if (error) {
-        node.hidden = false;
-        node.textContent = `${error}`;
-        _ankiSetErrorData(node, error);
+        const errorString = `${error}`;
+        if (node !== null) {
+            node.hidden = false;
+            node.textContent = errorString;
+            _ankiSetErrorData(node, error);
+        }
+
+        if (node2 !== null) {
+            node2.hidden = (errorString.indexOf('Invalid response') < 0);
+        }
     } else {
-        node.hidden = true;
-        node.textContent = '';
+        if (node !== null) {
+            node.hidden = true;
+            node.textContent = '';
+        }
+
+        if (node2 !== null) {
+            node2.hidden = true;
+        }
     }
 }
 
diff --git a/ext/bg/js/settings/audio-ui.js b/ext/bg/js/settings/audio-ui.js
index 711c2291..555380b4 100644
--- a/ext/bg/js/settings/audio-ui.js
+++ b/ext/bg/js/settings/audio-ui.js
@@ -16,7 +16,6 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-
 class AudioSourceUI {
     static instantiateTemplate(templateSelector) {
         const template = document.querySelector(templateSelector);
diff --git a/ext/bg/js/settings/audio.js b/ext/bg/js/settings/audio.js
index cff3f521..588d9a11 100644
--- a/ext/bg/js/settings/audio.js
+++ b/ext/bg/js/settings/audio.js
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+AudioSourceUI, audioGetTextToSpeechVoice*/
 
 let audioSourceUI = null;
 
diff --git a/ext/bg/js/settings/backup.js b/ext/bg/js/settings/backup.js
index becdc568..f4d622a4 100644
--- a/ext/bg/js/settings/backup.js
+++ b/ext/bg/js/settings/backup.js
@@ -16,6 +16,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGetFull, apiGetEnvironmentInfo
+utilBackend, utilIsolate, utilBackgroundIsolate, utilReadFileArrayBuffer
+optionsGetDefault, optionsUpdateVersion
+profileOptionsGetDefaultFieldTemplates*/
 
 // Exporting
 
@@ -159,7 +163,6 @@ async function _showSettingsImportWarnings(warnings) {
                 sanitize: e.currentTarget.dataset.importSanitize === 'true'
             });
             modalNode.modal('hide');
-
         };
         const onModalHide = () => {
             complete({result: false});
diff --git a/ext/bg/js/settings/conditions-ui.js b/ext/bg/js/settings/conditions-ui.js
index 4d041451..5a271321 100644
--- a/ext/bg/js/settings/conditions-ui.js
+++ b/ext/bg/js/settings/conditions-ui.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global conditionsNormalizeOptionValue*/
 
 class ConditionsUI {
     static instantiateTemplate(templateSelector) {
diff --git a/ext/bg/js/settings/dictionaries.js b/ext/bg/js/settings/dictionaries.js
index ed171ae9..70a22a16 100644
--- a/ext/bg/js/settings/dictionaries.js
+++ b/ext/bg/js/settings/dictionaries.js
@@ -16,6 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, getOptionsFullMutable, settingsSaveOptions, apiOptionsGetFull, apiOptionsGet
+utilBackgroundIsolate, utilDatabaseDeleteDictionary, utilDatabaseGetDictionaryInfo, utilDatabaseGetDictionaryCounts
+utilDatabasePurge, utilDatabaseImport
+storageUpdateStats, storageEstimate
+PageExitPrevention*/
 
 let dictionaryUI = null;
 
@@ -161,7 +166,7 @@ class SettingsDictionaryListUI {
         delete n.dataset.dict;
         $(n).modal('hide');
 
-        const index = this.dictionaryEntries.findIndex((e) => e.dictionaryInfo.title === title);
+        const index = this.dictionaryEntries.findIndex((entry) => entry.dictionaryInfo.title === title);
         if (index >= 0) {
             this.dictionaryEntries[index].deleteDictionary();
         }
@@ -174,7 +179,7 @@ class SettingsDictionaryEntryUI {
         this.dictionaryInfo = dictionaryInfo;
         this.optionsDictionary = optionsDictionary;
         this.counts = null;
-        this.eventListeners = [];
+        this.eventListeners = new EventListenerCollection();
         this.isDeleting = false;
 
         this.content = content;
@@ -193,10 +198,10 @@ class SettingsDictionaryEntryUI {
 
         this.applyValues();
 
-        this.addEventListener(this.enabledCheckbox, 'change', (e) => this.onEnabledChanged(e), false);
-        this.addEventListener(this.allowSecondarySearchesCheckbox, 'change', (e) => this.onAllowSecondarySearchesChanged(e), false);
-        this.addEventListener(this.priorityInput, 'change', (e) => this.onPriorityChanged(e), false);
-        this.addEventListener(this.deleteButton, 'click', (e) => this.onDeleteButtonClicked(e), false);
+        this.eventListeners.addEventListener(this.enabledCheckbox, 'change', (e) => this.onEnabledChanged(e), false);
+        this.eventListeners.addEventListener(this.allowSecondarySearchesCheckbox, 'change', (e) => this.onAllowSecondarySearchesChanged(e), false);
+        this.eventListeners.addEventListener(this.priorityInput, 'change', (e) => this.onPriorityChanged(e), false);
+        this.eventListeners.addEventListener(this.deleteButton, 'click', (e) => this.onDeleteButtonClicked(e), false);
     }
 
     cleanup() {
@@ -207,7 +212,7 @@ class SettingsDictionaryEntryUI {
             this.content = null;
         }
         this.dictionaryInfo = null;
-        this.clearEventListeners();
+        this.eventListeners.removeAllEventListeners();
     }
 
     setCounts(counts) {
@@ -224,18 +229,6 @@ class SettingsDictionaryEntryUI {
         this.parent.save();
     }
 
-    addEventListener(node, type, listener, options) {
-        node.addEventListener(type, listener, options);
-        this.eventListeners.push([node, type, listener, options]);
-    }
-
-    clearEventListeners() {
-        for (const [node, type, listener, options] of this.eventListeners) {
-            node.removeEventListener(type, listener, options);
-        }
-        this.eventListeners = [];
-    }
-
     applyValues() {
         this.enabledCheckbox.checked = this.optionsDictionary.enabled;
         this.allowSecondarySearchesCheckbox.checked = this.optionsDictionary.allowSecondarySearches;
@@ -272,9 +265,7 @@ class SettingsDictionaryEntryUI {
             this.isDeleting = false;
             progress.hidden = true;
 
-            const optionsContext = getOptionsContext();
-            const options = await getOptionsMutable(optionsContext);
-            onDatabaseUpdated(options);
+            onDatabaseUpdated();
         }
     }
 
@@ -359,28 +350,33 @@ async function dictSettingsInitialize() {
     document.querySelector('#dict-main').addEventListener('change', (e) => onDictionaryMainChanged(e), false);
     document.querySelector('#database-enable-prefix-wildcard-searches').addEventListener('change', (e) => onDatabaseEnablePrefixWildcardSearchesChanged(e), false);
 
-    const optionsContext = getOptionsContext();
-    const options = await getOptionsMutable(optionsContext);
-    onDictionaryOptionsChanged(options);
-    onDatabaseUpdated(options);
+    await onDictionaryOptionsChanged();
+    await onDatabaseUpdated();
 }
 
-async function onDictionaryOptionsChanged(options) {
+async function onDictionaryOptionsChanged() {
     if (dictionaryUI === null) { return; }
+
+    const optionsContext = getOptionsContext();
+    const options = await getOptionsMutable(optionsContext);
+
     dictionaryUI.setOptionsDictionaries(options.dictionaries);
 
     const optionsFull = await apiOptionsGetFull();
     document.querySelector('#database-enable-prefix-wildcard-searches').checked = optionsFull.global.database.prefixWildcardsSupported;
+
+    await updateMainDictionarySelectValue();
 }
 
-async function onDatabaseUpdated(options) {
+async function onDatabaseUpdated() {
     try {
         const dictionaries = await utilDatabaseGetDictionaryInfo();
         dictionaryUI.setDictionaries(dictionaries);
 
         document.querySelector('#dict-warning').hidden = (dictionaries.length > 0);
 
-        updateMainDictionarySelect(options, dictionaries);
+        updateMainDictionarySelectOptions(dictionaries);
+        await updateMainDictionarySelectValue();
 
         const {counts, total} = await utilDatabaseGetDictionaryCounts(dictionaries.map((v) => v.title), true);
         dictionaryUI.setCounts(counts, total);
@@ -389,7 +385,7 @@ async function onDatabaseUpdated(options) {
     }
 }
 
-async function updateMainDictionarySelect(options, dictionaries) {
+function updateMainDictionarySelectOptions(dictionaries) {
     const select = document.querySelector('#dict-main');
     select.textContent = ''; // Empty
 
@@ -399,8 +395,6 @@ async function updateMainDictionarySelect(options, dictionaries) {
     option.textContent = 'Not selected';
     select.appendChild(option);
 
-    let value = '';
-    const currentValue = options.general.mainDictionary;
     for (const {title, sequenced} of toIterable(dictionaries)) {
         if (!sequenced) { continue; }
 
@@ -408,26 +402,56 @@ async function updateMainDictionarySelect(options, dictionaries) {
         option.value = title;
         option.textContent = title;
         select.appendChild(option);
+    }
+}
+
+async function updateMainDictionarySelectValue() {
+    const optionsContext = getOptionsContext();
+    const options = await apiOptionsGet(optionsContext);
 
-        if (title === currentValue) {
-            value = title;
+    const value = options.general.mainDictionary;
+
+    const select = document.querySelector('#dict-main');
+    let selectValue = null;
+    for (const child of select.children) {
+        if (child.nodeName.toUpperCase() === 'OPTION' && child.value === value) {
+            selectValue = value;
+            break;
         }
     }
 
-    select.value = value;
-
-    if (options.general.mainDictionary !== value) {
-        options.general.mainDictionary = value;
-        settingsSaveOptions();
+    let missingNodeOption = select.querySelector('option[data-not-installed=true]');
+    if (selectValue === null) {
+        if (missingNodeOption === null) {
+            missingNodeOption = document.createElement('option');
+            missingNodeOption.className = 'text-muted';
+            missingNodeOption.value = value;
+            missingNodeOption.textContent = `${value} (Not installed)`;
+            missingNodeOption.dataset.notInstalled = 'true';
+            select.appendChild(missingNodeOption);
+        }
+    } else {
+        if (missingNodeOption !== null) {
+            missingNodeOption.parentNode.removeChild(missingNodeOption);
+        }
     }
+
+    select.value = value;
 }
 
 async function onDictionaryMainChanged(e) {
-    const value = e.target.value;
+    const select = e.target;
+    const value = select.value;
+
+    const missingNodeOption = select.querySelector('option[data-not-installed=true]');
+    if (missingNodeOption !== null && missingNodeOption.value !== value) {
+        missingNodeOption.parentNode.removeChild(missingNodeOption);
+    }
+
     const optionsContext = getOptionsContext();
     const options = await getOptionsMutable(optionsContext);
     options.general.mainDictionary = value;
-    settingsSaveOptions();
+    await settingsSaveOptions();
 }
 
 
@@ -467,15 +491,18 @@ function dictionaryErrorsShow(errors) {
     dialog.textContent = '';
 
     if (errors !== null && errors.length > 0) {
-        const uniqueErrors = {};
+        const uniqueErrors = new Map();
         for (let e of errors) {
             console.error(e);
             e = dictionaryErrorToString(e);
-            uniqueErrors[e] = hasOwn(uniqueErrors, e) ? uniqueErrors[e] + 1 : 1;
+            let count = uniqueErrors.get(e);
+            if (typeof count === 'undefined') {
+                count = 0;
+            }
+            uniqueErrors.set(e, count + 1);
         }
 
-        for (const e in uniqueErrors) {
-            const count = uniqueErrors[e];
+        for (const [e, count] of uniqueErrors.entries()) {
             const div = document.createElement('p');
             if (count > 1) {
                 div.textContent = `${e} `;
@@ -537,9 +564,7 @@ async function onDictionaryPurge(e) {
         }
         await settingsSaveOptions();
 
-        const optionsContext = getOptionsContext();
-        const options = await getOptionsMutable(optionsContext);
-        onDatabaseUpdated(options);
+        onDatabaseUpdated();
     } catch (err) {
         dictionaryErrorsShow([err]);
     } finally {
@@ -611,9 +636,7 @@ async function onDictionaryImport(e) {
                 dictionaryErrorsShow(errors);
             }
 
-            const optionsContext = getOptionsContext();
-            const options = await getOptionsMutable(optionsContext);
-            onDatabaseUpdated(options);
+            onDatabaseUpdated();
         }
     } catch (err) {
         dictionaryErrorsShow([err]);
diff --git a/ext/bg/js/settings/main.js b/ext/bg/js/settings/main.js
index 3bf65eda..d1ad2c6b 100644
--- a/ext/bg/js/settings/main.js
+++ b/ext/bg/js/settings/main.js
@@ -16,6 +16,14 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, apiOptionsSave
+utilBackend, utilIsolate, utilBackgroundIsolate
+ankiErrorShown, ankiFieldsToDict
+ankiTemplatesUpdateValue, onAnkiOptionsChanged, onDictionaryOptionsChanged
+appearanceInitialize, audioSettingsInitialize, profileOptionsSetup, dictSettingsInitialize
+ankiInitialize, ankiTemplatesInitialize, storageInfoInitialize
+*/
+
 function getOptionsMutable(optionsContext) {
     return utilBackend().getOptions(
         utilBackgroundIsolate(optionsContext)
@@ -28,6 +36,22 @@ function getOptionsFullMutable() {
 
 async function formRead(options) {
     options.general.enable = $('#enable').prop('checked');
+    const enableClipboardPopups = $('#enable-clipboard-popups').prop('checked');
+    if (enableClipboardPopups) {
+        options.general.enableClipboardPopups = await new Promise((resolve, _reject) => {
+            chrome.permissions.request(
+                {permissions: ['clipboardRead']},
+                (granted) => {
+                    if (!granted) {
+                        $('#enable-clipboard-popups').prop('checked', false);
+                    }
+                    resolve(granted);
+                }
+            );
+        });
+    } else {
+        options.general.enableClipboardPopups = false;
+    }
     options.general.showGuide = $('#show-usage-guide').prop('checked');
     options.general.compactTags = $('#compact-tags').prop('checked');
     options.general.compactGlossaries = $('#compact-glossaries').prop('checked');
@@ -44,7 +68,7 @@ async function formRead(options) {
     options.general.popupVerticalOffset = parseInt($('#popup-vertical-offset').val(), 10);
     options.general.popupHorizontalOffset2 = parseInt($('#popup-horizontal-offset2').val(), 0);
     options.general.popupVerticalOffset2 = parseInt($('#popup-vertical-offset2').val(), 10);
-    options.general.popupScalingFactor = parseInt($('#popup-scaling-factor').val(), 10);
+    options.general.popupScalingFactor = parseFloat($('#popup-scaling-factor').val());
     options.general.popupScaleRelativeToPageZoom = $('#popup-scale-relative-to-page-zoom').prop('checked');
     options.general.popupScaleRelativeToVisualViewport = $('#popup-scale-relative-to-visual-viewport').prop('checked');
     options.general.popupTheme = $('#popup-theme').val();
@@ -67,6 +91,7 @@ async function formRead(options) {
     options.scanning.enablePopupSearch = $('#enable-search-within-first-popup').prop('checked');
     options.scanning.enableOnPopupExpressions = $('#enable-scanning-of-popup-expressions').prop('checked');
     options.scanning.enableOnSearchPage = $('#enable-scanning-on-search-page').prop('checked');
+    options.scanning.enableSearchTags = $('#enable-search-tags').prop('checked');
     options.scanning.delay = parseInt($('#scan-delay').val(), 10);
     options.scanning.length = parseInt($('#scan-length').val(), 10);
     options.scanning.modifier = $('#scan-modifier-key').val();
@@ -103,6 +128,7 @@ async function formRead(options) {
 
 async function formWrite(options) {
     $('#enable').prop('checked', options.general.enable);
+    $('#enable-clipboard-popups').prop('checked', options.general.enableClipboardPopups);
     $('#show-usage-guide').prop('checked', options.general.showGuide);
     $('#compact-tags').prop('checked', options.general.compactTags);
     $('#compact-glossaries').prop('checked', options.general.compactGlossaries);
@@ -142,6 +168,7 @@ async function formWrite(options) {
     $('#enable-search-within-first-popup').prop('checked', options.scanning.enablePopupSearch);
     $('#enable-scanning-of-popup-expressions').prop('checked', options.scanning.enableOnPopupExpressions);
     $('#enable-scanning-on-search-page').prop('checked', options.scanning.enableOnSearchPage);
+    $('#enable-search-tags').prop('checked', options.scanning.enableSearchTags);
     $('#scan-delay').val(options.scanning.delay);
     $('#scan-length').val(options.scanning.length);
     $('#scan-modifier-key').val(options.scanning.modifier);
@@ -167,7 +194,7 @@ async function formWrite(options) {
 
     await ankiTemplatesUpdateValue();
     await onAnkiOptionsChanged(options);
-    await onDictionaryOptionsChanged(options);
+    await onDictionaryOptionsChanged();
 
     formUpdateVisibility(options);
 }
@@ -215,7 +242,7 @@ async function settingsSaveOptions() {
     await apiOptionsSave(source);
 }
 
-async function onOptionsUpdate({source}) {
+async function onOptionsUpdated({source}) {
     const thisSource = await settingsGetSource();
     if (source === thisSource) { return; }
 
@@ -247,7 +274,7 @@ async function onReady() {
 
     storageInfoInitialize();
 
-    yomichan.on('optionsUpdate', onOptionsUpdate);
+    yomichan.on('optionsUpdated', onOptionsUpdated);
 }
 
 $(document).ready(() => onReady());
diff --git a/ext/bg/js/settings/popup-preview-frame.js b/ext/bg/js/settings/popup-preview-frame.js
index 37a4b416..aa2b6100 100644
--- a/ext/bg/js/settings/popup-preview-frame.js
+++ b/ext/bg/js/settings/popup-preview-frame.js
@@ -16,15 +16,18 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGet, Popup, PopupProxyHost, Frontend, TextSourceRange*/
 
 class SettingsPopupPreview {
     constructor() {
         this.frontend = null;
         this.apiOptionsGetOld = apiOptionsGet;
-        this.popupInjectOuterStylesheetOld = Popup.injectOuterStylesheet;
+        this.popup = null;
+        this.popupSetCustomOuterCssOld = null;
         this.popupShown = false;
         this.themeChangeTimeout = null;
         this.textSource = null;
+        this._targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
     }
 
     static create() {
@@ -49,18 +52,18 @@ class SettingsPopupPreview {
         const popupHost = new PopupProxyHost();
         await popupHost.prepare();
 
-        const popup = popupHost.createPopup(null, 0);
-        popup.setChildrenSupported(false);
+        this.popup = popupHost.getOrCreatePopup();
+        this.popup.setChildrenSupported(false);
 
-        this.frontend = new Frontend(popup);
+        this.popupSetCustomOuterCssOld = this.popup.setCustomOuterCss;
+        this.popup.setCustomOuterCss = (...args) => this.popupSetCustomOuterCss(...args);
 
-        this.frontend.setEnabled = function () {};
-        this.frontend.searchClear = function () {};
+        this.frontend = new Frontend(this.popup);
 
-        await this.frontend.prepare();
+        this.frontend.setEnabled = () => {};
+        this.frontend.searchClear = () => {};
 
-        // Overwrite popup
-        Popup.injectOuterStylesheet = (...args) => this.popupInjectOuterStylesheet(...args);
+        await this.frontend.prepare();
 
         // Update search
         this.updateSearch();
@@ -82,20 +85,21 @@ class SettingsPopupPreview {
         return options;
     }
 
-    popupInjectOuterStylesheet(...args) {
+    async popupSetCustomOuterCss(...args) {
         // This simulates the stylesheet priorities when injecting using the web extension API.
-        const result = this.popupInjectOuterStylesheetOld(...args);
+        const result = await this.popupSetCustomOuterCssOld.call(this.popup, ...args);
 
-        const outerStylesheet = Popup.outerStylesheet;
         const node = document.querySelector('#client-css');
-        if (node !== null && outerStylesheet !== null) {
-            node.parentNode.insertBefore(outerStylesheet, node);
+        if (node !== null && result !== null) {
+            node.parentNode.insertBefore(result, node);
         }
 
         return result;
     }
 
     onMessage(e) {
+        if (e.origin !== this._targetOrigin) { return; }
+
         const {action, params} = e.data;
         const handler = SettingsPopupPreview._messageHandlers.get(action);
         if (typeof handler !== 'function') { return; }
@@ -136,7 +140,7 @@ class SettingsPopupPreview {
 
     setCustomOuterCss(css) {
         if (this.frontend === null) { return; }
-        this.frontend.popup.setCustomOuterCss(css, true);
+        this.frontend.popup.setCustomOuterCss(css, false);
     }
 
     async updateSearch() {
diff --git a/ext/bg/js/settings/popup-preview.js b/ext/bg/js/settings/popup-preview.js
index 0d20471e..d1d2ff5e 100644
--- a/ext/bg/js/settings/popup-preview.js
+++ b/ext/bg/js/settings/popup-preview.js
@@ -40,20 +40,22 @@ function showAppearancePreview() {
 
     window.wanakana.bind(text[0]);
 
+    const targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
+
     text.on('input', () => {
         const action = 'setText';
         const params = {text: text.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
     customCss.on('input', () => {
         const action = 'setCustomCss';
         const params = {css: customCss.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
     customOuterCss.on('input', () => {
         const action = 'setCustomOuterCss';
         const params = {css: customOuterCss.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
 
     container.append(frame);
diff --git a/ext/bg/js/settings/profiles.js b/ext/bg/js/settings/profiles.js
index c4e68b53..3e589809 100644
--- a/ext/bg/js/settings/profiles.js
+++ b/ext/bg/js/settings/profiles.js
@@ -16,6 +16,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsMutable, getOptionsFullMutable, settingsSaveOptions, apiOptionsGetFull
+utilBackgroundIsolate, formWrite
+conditionsClearCaches, ConditionsUI, profileConditionsDescriptor*/
+
 let currentProfileIndex = 0;
 let profileConditionsContainer = null;
 
diff --git a/ext/bg/js/settings/storage.js b/ext/bg/js/settings/storage.js
index 6c10f665..cbe1bb4d 100644
--- a/ext/bg/js/settings/storage.js
+++ b/ext/bg/js/settings/storage.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiGetEnvironmentInfo*/
 
 function storageBytesToLabeledString(size) {
     const base = 1000;
diff --git a/ext/bg/js/templates.js b/ext/bg/js/templates.js
deleted file mode 100644
index 2f65be31..00000000
--- a/ext/bg/js/templates.js
+++ /dev/null
@@ -1,55 +0,0 @@
-(function() {
-  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-templates['query-parser.html'] = template({"1":function(container,depth0,helpers,partials,data) {
-    var stack1, alias1=depth0 != null ? depth0 : (container.nullContext || {});
-
-  return ((stack1 = helpers["if"].call(alias1,(depth0 != null ? depth0.preview : depth0),{"name":"if","hash":{},"fn":container.program(2, data, 0),"inverse":container.program(4, data, 0),"data":data})) != null ? stack1 : "")
-    + ((stack1 = helpers.each.call(alias1,depth0,{"name":"each","hash":{},"fn":container.program(6, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "")
-    + "</span>";
-},"2":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-term-preview\">";
-},"4":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-term\">";
-},"6":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = container.invokePartial(partials.part,depth0,{"name":"part","data":data,"helpers":helpers,"partials":partials,"decorators":container.decorators})) != null ? stack1 : "");
-},"8":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = helpers["if"].call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.raw : depth0),{"name":"if","hash":{},"fn":container.program(9, data, 0),"inverse":container.program(12, data, 0),"data":data})) != null ? stack1 : "");
-},"9":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = helpers.each.call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.text : depth0),{"name":"each","hash":{},"fn":container.program(10, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "");
-},"10":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-char\">"
-    + container.escapeExpression(container.lambda(depth0, depth0))
-    + "</span>";
-},"12":function(container,depth0,helpers,partials,data) {
-    var stack1, helper, alias1=depth0 != null ? depth0 : (container.nullContext || {});
-
-  return "<ruby>"
-    + ((stack1 = helpers.each.call(alias1,(depth0 != null ? depth0.text : depth0),{"name":"each","hash":{},"fn":container.program(10, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "")
-    + "<rt>"
-    + container.escapeExpression(((helper = (helper = helpers.reading || (depth0 != null ? depth0.reading : depth0)) != null ? helper : helpers.helperMissing),(typeof helper === "function" ? helper.call(alias1,{"name":"reading","hash":{},"data":data}) : helper)))
-    + "</rt></ruby>";
-},"14":function(container,depth0,helpers,partials,data,blockParams,depths) {
-    var stack1;
-
-  return ((stack1 = container.invokePartial(partials.term,depth0,{"name":"term","hash":{"preview":(depths[1] != null ? depths[1].preview : depths[1])},"data":data,"helpers":helpers,"partials":partials,"decorators":container.decorators})) != null ? stack1 : "");
-},"compiler":[7,">= 4.0.0"],"main":function(container,depth0,helpers,partials,data,blockParams,depths) {
-    var stack1;
-
-  return ((stack1 = helpers.each.call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.terms : depth0),{"name":"each","hash":{},"fn":container.program(14, data, 0, blockParams, depths),"inverse":container.noop,"data":data})) != null ? stack1 : "");
-},"main_d":  function(fn, props, container, depth0, data, blockParams, depths) {
-
-  var decorators = container.decorators;
-
-  fn = decorators.inline(fn,props,container,{"name":"inline","hash":{},"fn":container.program(1, data, 0, blockParams, depths),"inverse":container.noop,"args":["term"],"data":data}) || fn;
-  fn = decorators.inline(fn,props,container,{"name":"inline","hash":{},"fn":container.program(8, data, 0, blockParams, depths),"inverse":container.noop,"args":["part"],"data":data}) || fn;
-  return fn;
-  }
-
-,"useDecorators":true,"usePartial":true,"useData":true,"useDepths":true});
-})();
\ No newline at end of file
diff --git a/ext/bg/js/translator.js b/ext/bg/js/translator.js
index dfec54ac..a675a9f7 100644
--- a/ext/bg/js/translator.js
+++ b/ext/bg/js/translator.js
@@ -16,12 +16,18 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global requestJson
+dictTermsMergeBySequence, dictTagBuildSource, dictTermsMergeByGloss, dictTermsSort, dictTagsSort
+dictEnabledSet, dictTermsGroup, dictTermsCompressTags, dictTermsUndupe, dictTagSanitize
+jpDistributeFurigana, jpConvertHalfWidthKanaToFullWidth, jpConvertNumericTofullWidth
+jpConvertAlphabeticToKana, jpHiraganaToKatakana, jpKatakanaToHiragana, jpIsCharCodeJapanese
+Database, Deinflector*/
 
 class Translator {
     constructor() {
         this.database = null;
         this.deinflector = null;
-        this.tagCache = {};
+        this.tagCache = new Map();
     }
 
     async prepare() {
@@ -38,24 +44,24 @@ class Translator {
     }
 
     async purgeDatabase() {
-        this.tagCache = {};
+        this.tagCache.clear();
         await this.database.purge();
     }
 
     async deleteDictionary(dictionaryName) {
-        this.tagCache = {};
+        this.tagCache.clear();
         await this.database.deleteDictionary(dictionaryName);
     }
 
     async getSequencedDefinitions(definitions, mainDictionary) {
-        const definitionsBySequence = dictTermsMergeBySequence(definitions, mainDictionary);
-        const defaultDefinitions = definitionsBySequence['-1'];
+        const [definitionsBySequence, defaultDefinitions] = dictTermsMergeBySequence(definitions, mainDictionary);
 
-        const sequenceList = Object.keys(definitionsBySequence).map((v) => Number(v)).filter((v) => v >= 0);
-        const sequencedDefinitions = sequenceList.map((key) => ({
-            definitions: definitionsBySequence[key],
-            rawDefinitions: []
-        }));
+        const sequenceList = [];
+        const sequencedDefinitions = [];
+        for (const [key, value] of definitionsBySequence.entries()) {
+            sequenceList.push(key);
+            sequencedDefinitions.push({definitions: value, rawDefinitions: []});
+        }
 
         for (const definition of await this.database.findTermsBySequenceBulk(sequenceList, mainDictionary)) {
             sequencedDefinitions[definition.index].rawDefinitions.push(definition);
@@ -64,8 +70,8 @@ class Translator {
         return {sequencedDefinitions, defaultDefinitions};
     }
 
-    async getMergedSecondarySearchResults(text, expressionsMap, secondarySearchTitles) {
-        if (secondarySearchTitles.length === 0) {
+    async getMergedSecondarySearchResults(text, expressionsMap, secondarySearchDictionaries) {
+        if (secondarySearchDictionaries.size === 0) {
             return [];
         }
 
@@ -79,7 +85,7 @@ class Translator {
             }
         }
 
-        const definitions = await this.database.findTermsExactBulk(expressionList, readingList, secondarySearchTitles);
+        const definitions = await this.database.findTermsExactBulk(expressionList, readingList, secondarySearchDictionaries);
         for (const definition of definitions) {
             const definitionTags = await this.expandTags(definition.definitionTags, definition.dictionary);
             definitionTags.push(dictTagBuildSource(definition.dictionary));
@@ -95,7 +101,7 @@ class Translator {
         return definitions;
     }
 
-    async getMergedDefinition(text, dictionaries, sequencedDefinition, defaultDefinitions, secondarySearchTitles, mergedByTermIndices) {
+    async getMergedDefinition(text, dictionaries, sequencedDefinition, defaultDefinitions, secondarySearchDictionaries, mergedByTermIndices) {
         const result = sequencedDefinition.definitions;
         const rawDefinitionsBySequence = sequencedDefinition.rawDefinitions;
 
@@ -108,12 +114,11 @@ class Translator {
         }
 
         const definitionsByGloss = dictTermsMergeByGloss(result, rawDefinitionsBySequence);
-        const secondarySearchResults = await this.getMergedSecondarySearchResults(text, result.expressions, secondarySearchTitles);
+        const secondarySearchResults = await this.getMergedSecondarySearchResults(text, result.expressions, secondarySearchDictionaries);
 
         dictTermsMergeByGloss(result, defaultDefinitions.concat(secondarySearchResults), definitionsByGloss, mergedByTermIndices);
 
-        for (const gloss in definitionsByGloss) {
-            const definition = definitionsByGloss[gloss];
+        for (const definition of definitionsByGloss.values()) {
             dictTagsSort(definition.definitionTags);
             result.definitions.push(definition);
         }
@@ -122,7 +127,8 @@ class Translator {
 
         const expressions = [];
         for (const [expression, readingMap] of result.expressions.entries()) {
-            for (const [reading, termTags] of readingMap.entries()) {
+            for (const [reading, termTagsMap] of readingMap.entries()) {
+                const termTags = [...termTagsMap.values()];
                 const score = termTags.map((tag) => tag.score).reduce((p, v) => p + v, 0);
                 expressions.push(Translator.createExpression(expression, reading, dictTagsSort(termTags), Translator.scoreToTermFrequency(score)));
             }
@@ -135,14 +141,16 @@ class Translator {
         return result;
     }
 
-    async findTerms(text, details, options) {
-        switch (options.general.resultOutputMode) {
+    async findTerms(mode, text, details, options) {
+        switch (mode) {
             case 'group':
                 return await this.findTermsGrouped(text, details, options);
             case 'merge':
                 return await this.findTermsMerged(text, details, options);
             case 'split':
                 return await this.findTermsSplit(text, details, options);
+            case 'simple':
+                return await this.findTermsSimple(text, details, options);
             default:
                 return [[], 0];
         }
@@ -150,11 +158,10 @@ class Translator {
 
     async findTermsGrouped(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
 
         const definitionsGrouped = dictTermsGroup(definitions, dictionaries);
-        await this.buildTermMeta(definitionsGrouped, titles);
+        await this.buildTermMeta(definitionsGrouped, dictionaries);
 
         if (options.general.compactTags) {
             for (const definition of definitionsGrouped) {
@@ -167,8 +174,12 @@ class Translator {
 
     async findTermsMerged(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const secondarySearchTitles = Object.keys(options.dictionaries).filter((dict) => options.dictionaries[dict].allowSecondarySearches);
-        const titles = Object.keys(dictionaries);
+        const secondarySearchDictionaries = new Map();
+        for (const [title, dictionary] of dictionaries.entries()) {
+            if (!dictionary.allowSecondarySearches) { continue; }
+            secondarySearchDictionaries.set(title, dictionary);
+        }
+
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
         const {sequencedDefinitions, defaultDefinitions} = await this.getSequencedDefinitions(definitions, options.general.mainDictionary);
         const definitionsMerged = [];
@@ -180,7 +191,7 @@ class Translator {
                 dictionaries,
                 sequencedDefinition,
                 defaultDefinitions,
-                secondarySearchTitles,
+                secondarySearchDictionaries,
                 mergedByTermIndices
             );
             definitionsMerged.push(result);
@@ -192,7 +203,7 @@ class Translator {
             definitionsMerged.push(groupedDefinition);
         }
 
-        await this.buildTermMeta(definitionsMerged, titles);
+        await this.buildTermMeta(definitionsMerged, dictionaries);
 
         if (options.general.compactTags) {
             for (const definition of definitionsMerged) {
@@ -205,25 +216,28 @@ class Translator {
 
     async findTermsSplit(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
 
-        await this.buildTermMeta(definitions, titles);
+        await this.buildTermMeta(definitions, dictionaries);
 
         return [definitions, length];
     }
 
+    async findTermsSimple(text, details, options) {
+        const dictionaries = dictEnabledSet(options);
+        return await this.findTermsInternal(text, dictionaries, details, options);
+    }
+
     async findTermsInternal(text, dictionaries, details, options) {
         text = Translator.getSearchableText(text, options);
         if (text.length === 0) {
             return [[], 0];
         }
 
-        const titles = Object.keys(dictionaries);
         const deinflections = (
             details.wildcard ?
-            await this.findTermWildcard(text, titles, details.wildcard) :
-            await this.findTermDeinflections(text, titles, options)
+            await this.findTermWildcard(text, dictionaries, details.wildcard) :
+            await this.findTermDeinflections(text, dictionaries, options)
         );
 
         let definitions = [];
@@ -265,8 +279,8 @@ class Translator {
         return [definitions, length];
     }
 
-    async findTermWildcard(text, titles, wildcard) {
-        const definitions = await this.database.findTermsBulk([text], titles, wildcard);
+    async findTermWildcard(text, dictionaries, wildcard) {
+        const definitions = await this.database.findTermsBulk([text], dictionaries, wildcard);
         if (definitions.length === 0) {
             return [];
         }
@@ -281,7 +295,7 @@ class Translator {
         }];
     }
 
-    async findTermDeinflections(text, titles, options) {
+    async findTermDeinflections(text, dictionaries, options) {
         const deinflections = this.getAllDeinflections(text, options);
 
         if (deinflections.length === 0) {
@@ -303,7 +317,7 @@ class Translator {
             deinflectionArray.push(deinflection);
         }
 
-        const definitions = await this.database.findTermsBulk(uniqueDeinflectionTerms, titles, null);
+        const definitions = await this.database.findTermsBulk(uniqueDeinflectionTerms, dictionaries, null);
 
         for (const definition of definitions) {
             const definitionRules = Deinflector.rulesToRuleFlags(definition.rules);
@@ -393,17 +407,12 @@ class Translator {
 
     async findKanji(text, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
-        const kanjiUnique = {};
-        const kanjiList = [];
+        const kanjiUnique = new Set();
         for (const c of text) {
-            if (!hasOwn(kanjiUnique, c)) {
-                kanjiList.push(c);
-                kanjiUnique[c] = true;
-            }
+            kanjiUnique.add(c);
         }
 
-        const definitions = await this.database.findKanjiBulk(kanjiList, titles);
+        const definitions = await this.database.findKanjiBulk([...kanjiUnique], dictionaries);
         if (definitions.length === 0) {
             return definitions;
         }
@@ -423,12 +432,12 @@ class Translator {
             definition.stats = stats;
         }
 
-        await this.buildKanjiMeta(definitions, titles);
+        await this.buildKanjiMeta(definitions, dictionaries);
 
         return definitions;
     }
 
-    async buildTermMeta(definitions, titles) {
+    async buildTermMeta(definitions, dictionaries) {
         const terms = [];
         for (const definition of definitions) {
             if (definition.expressions) {
@@ -454,7 +463,7 @@ class Translator {
                 termList = [];
                 expressionsUnique.push(expression);
                 termsUnique.push(termList);
-                termsUniqueMap[expression] = termList;
+                termsUniqueMap.set(expression, termList);
             }
             termList.push(term);
 
@@ -462,7 +471,7 @@ class Translator {
             term.frequencies = [];
         }
 
-        const metas = await this.database.findTermMetaBulk(expressionsUnique, titles);
+        const metas = await this.database.findTermMetaBulk(expressionsUnique, dictionaries);
         for (const {expression, mode, data, dictionary, index} of metas) {
             switch (mode) {
                 case 'freq':
@@ -474,14 +483,14 @@ class Translator {
         }
     }
 
-    async buildKanjiMeta(definitions, titles) {
+    async buildKanjiMeta(definitions, dictionaries) {
         const kanjiList = [];
         for (const definition of definitions) {
             kanjiList.push(definition.character);
             definition.frequencies = [];
         }
 
-        const metas = await this.database.findKanjiMetaBulk(kanjiList, titles);
+        const metas = await this.database.findKanjiMetaBulk(kanjiList, dictionaries);
         for (const {character, mode, data, dictionary, index} of metas) {
             switch (mode) {
                 case 'freq':
@@ -504,49 +513,50 @@ class Translator {
         const names = Object.keys(items);
         const tagMetaList = await this.getTagMetaList(names, title);
 
-        const stats = {};
+        const statsGroups = new Map();
         for (let i = 0; i < names.length; ++i) {
             const name = names[i];
             const meta = tagMetaList[i];
             if (meta === null) { continue; }
 
             const category = meta.category;
-            const group = (
-                hasOwn(stats, category) ?
-                stats[category] :
-                (stats[category] = [])
-            );
+            let group = statsGroups.get(category);
+            if (typeof group === 'undefined') {
+                group = [];
+                statsGroups.set(category, group);
+            }
 
             const stat = Object.assign({}, meta, {name, value: items[name]});
             group.push(dictTagSanitize(stat));
         }
 
+        const stats = {};
         const sortCompare = (a, b) => a.notes - b.notes;
-        for (const category in stats) {
-            stats[category].sort(sortCompare);
+        for (const [category, group] of statsGroups.entries()) {
+            group.sort(sortCompare);
+            stats[category] = group;
         }
-
         return stats;
     }
 
     async getTagMetaList(names, title) {
         const tagMetaList = [];
-        const cache = (
-            hasOwn(this.tagCache, title) ?
-            this.tagCache[title] :
-            (this.tagCache[title] = {})
-        );
+        let cache = this.tagCache.get(title);
+        if (typeof cache === 'undefined') {
+            cache = new Map();
+            this.tagCache.set(title, cache);
+        }
 
         for (const name of names) {
             const base = Translator.getNameBase(name);
 
-            if (hasOwn(cache, base)) {
-                tagMetaList.push(cache[base]);
-            } else {
-                const tagMeta = await this.database.findTagForTitle(base, title);
-                cache[base] = tagMeta;
-                tagMetaList.push(tagMeta);
+            let tagMeta = cache.get(base);
+            if (typeof tagMeta === 'undefined') {
+                tagMeta = await this.database.findTagForTitle(base, title);
+                cache.set(base, tagMeta);
             }
+
+            tagMetaList.push(tagMeta);
         }
 
         return tagMetaList;
diff --git a/ext/bg/js/util.js b/ext/bg/js/util.js
index 333e814b..5ce4b08c 100644
--- a/ext/bg/js/util.js
+++ b/ext/bg/js/util.js
@@ -33,7 +33,7 @@ function utilIsolate(value) {
 }
 
 function utilFunctionIsolate(func) {
-    return function (...args) {
+    return function isolatedFunction(...args) {
         try {
             args = args.map((v) => utilIsolate(v));
             return func.call(this, ...args);
@@ -59,32 +59,6 @@ function utilBackgroundFunctionIsolate(func) {
     return backgroundPage.utilFunctionIsolate(func);
 }
 
-function utilSetEqual(setA, setB) {
-    if (setA.size !== setB.size) {
-        return false;
-    }
-
-    for (const value of setA) {
-        if (!setB.has(value)) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-function utilSetIntersection(setA, setB) {
-    return new Set(
-        [...setA].filter((value) => setB.has(value))
-    );
-}
-
-function utilSetDifference(setA, setB) {
-    return new Set(
-        [...setA].filter((value) => !setB.has(value))
-    );
-}
-
 function utilStringHashCode(string) {
     let hashCode = 0;
 
diff --git a/ext/bg/query-parser-templates.html b/ext/bg/query-parser-templates.html
new file mode 100644
index 00000000..7cab16a9
--- /dev/null
+++ b/ext/bg/query-parser-templates.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html><html><head></head><body>
+
+<template id="term-template"><span class="query-parser-term" data-type="normal"></span></template>
+<template id="term-preview-template"><span class="query-parser-term" data-type="preview"></span></template>
+<template id="segment-template"><ruby class="query-parser-segment"><span class="query-parser-segment-text"></span><rt class="query-parser-segment-reading"></rt></ruby></template>
+<template id="char-template"><span class="query-parser-char"></span></template>
+
+<template id="select-template"><select class="query-parser-select form-control"></select></template>
+<template id="select-option-template"><option class="query-parser-select-option"></option></template>
+
+</body></html>
diff --git a/ext/bg/search.html b/ext/bg/search.html
index 74afbb68..d6336826 100644
--- a/ext/bg/search.html
+++ b/ext/bg/search.html
@@ -25,29 +25,31 @@
                 <p style="margin-bottom: 0;">Search your installed dictionaries by entering a Japanese expression into the field below.</p>
             </div>
 
-            <div class="input-group" style="padding-top: 20px;">
-                <span title="Enable kana input method" class="input-group-text">
-                    <input type="checkbox" id="wanakana-enable" class="icon-checkbox" />
-                    <label for="wanakana-enable" class="scan-disable">あ</label>
-                </span>
-                <span title="Enable clipboard monitor" class="input-group-text">
-                    <input type="checkbox" id="clipboard-monitor-enable" class="icon-checkbox" />
-                    <label for="clipboard-monitor-enable"><span class="glyphicon glyphicon-paste"></span></label>
-                </span>
-            </div>
+            <div class="search-input">
+                <div class="input-group" style="padding-top: 20px;">
+                    <span title="Enable kana input method" class="input-group-text">
+                        <input type="checkbox" id="wanakana-enable" class="icon-checkbox" />
+                        <label for="wanakana-enable" class="scan-disable">あ</label>
+                    </span>
+                    <span title="Enable clipboard monitor" class="input-group-text">
+                        <input type="checkbox" id="clipboard-monitor-enable" class="icon-checkbox" />
+                        <label for="clipboard-monitor-enable"><span class="glyphicon glyphicon-paste"></span></label>
+                    </span>
+                </div>
 
-            <form class="input-group">
-                <input type="text" class="form-control" placeholder="Search for..." id="query" autofocus>
-                <span class="input-group-btn">
-                    <input type="submit" class="btn btn-default form-control" id="search" value="Search">
-                </span>
-            </form>
+                <form class="input-group">
+                    <input type="text" class="form-control" placeholder="Search for..." id="query" autofocus>
+                    <span class="input-group-btn">
+                        <input type="submit" class="btn btn-default form-control" id="search" value="Search">
+                    </span>
+                </form>
+            </div>
 
             <div id="spinner" hidden><img src="/mixed/img/spinner.gif"></div>
 
             <div class="scan-disable">
-                <div id="query-parser-select" class="input-group"></div>
-                <div id="query-parser"></div>
+                <div id="query-parser-select-container" class="input-group"></div>
+                <div id="query-parser-content"></div>
             </div>
 
             <hr>
@@ -75,18 +77,20 @@
 
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
-        <script src="/bg/js/templates.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/fg/js/document.js"></script>
         <script src="/fg/js/source.js"></script>
         <script src="/mixed/js/audio.js"></script>
         <script src="/mixed/js/display-context.js"></script>
         <script src="/mixed/js/display.js"></script>
         <script src="/mixed/js/display-generator.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
         <script src="/mixed/js/scroll.js"></script>
         <script src="/mixed/js/text-scanner.js"></script>
+        <script src="/mixed/js/template-handler.js"></script>
 
+        <script src="/bg/js/search-query-parser-generator.js"></script>
         <script src="/bg/js/search-query-parser.js"></script>
+        <script src="/bg/js/clipboard-monitor.js"></script>
         <script src="/bg/js/search.js"></script>
         <script src="/bg/js/search-frontend.js"></script>
     </body>
diff --git a/ext/bg/settings.html b/ext/bg/settings.html
index 3e06d4b5..b048a36c 100644
--- a/ext/bg/settings.html
+++ b/ext/bg/settings.html
@@ -134,6 +134,10 @@
                     <label><input type="checkbox" id="enable"> Enable content scanning</label>
                 </div>
 
+                <div class="checkbox" data-hide-for-browser="firefox-mobile">
+                    <label><input type="checkbox" id="enable-clipboard-popups"> Enable native popups when copying Japanese text</label>
+                </div>
+
                 <div class="checkbox">
                     <label><input type="checkbox" id="show-usage-guide"> Show usage guide on startup</label>
                 </div>
@@ -481,7 +485,7 @@
                 </p>
 
                 <div class="checkbox">
-                    <label><input type="checkbox" id="enable-search-within-first-popup"> Enable search when clicking glossary entries</label>
+                    <label><input type="checkbox" id="enable-search-within-first-popup"> Enable search when clicking glossary entries and tags</label>
                 </div>
 
                 <div class="checkbox">
@@ -492,6 +496,10 @@
                     <label><input type="checkbox" id="enable-scanning-of-popup-expressions"> Enable scanning of expressions in search results</label>
                 </div>
 
+                <div class="checkbox">
+                    <label><input type="checkbox" id="enable-search-tags"> Enable clickable and scannable tags for searching expressions and their readings</label>
+                </div>
+
                 <div class="form-group">
                     <label for="popup-nesting-max-depth">Maximum number of additional popups</label>
                     <input type="number" min="0" step="1" id="popup-nesting-max-depth" class="form-control">
@@ -760,6 +768,13 @@
 
                     <div class="alert alert-danger" id="anki-error" hidden></div>
 
+                    <div class="alert alert-danger" id="anki-invalid-response-error" hidden>
+                        Attempting to connect to Anki can sometimes return an error message which includes "Invalid response",
+                        which may indicate that the value of the <strong>Interface server</strong> option is incorrect.
+                        The <strong>Show advanced options</strong> checkbox under General Options must be ticked ticked to show this option.
+                        Resetting it to the default value may fix issues that are occurring.
+                    </div>
+
                     <div class="form-group">
                         <label for="card-tags">Card tags <span class="label-light">(comma or space separated)</span></label>
                         <input type="text" id="card-tags" class="form-control">
@@ -771,7 +786,7 @@
                     </div>
 
                     <div class="form-group options-advanced">
-                        <label for="interface-server">Interface server</label>
+                        <label for="interface-server">Interface server <span class="label-light">(Default: http://127.0.0.1:8765)</span></label>
                         <input type="text" id="interface-server" class="form-control">
                     </div>
 
@@ -1073,16 +1088,15 @@
         <script src="/mixed/js/core.js"></script>
         <script src="/mixed/js/dom.js"></script>
         <script src="/mixed/js/api.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
 
         <script src="/bg/js/anki.js"></script>
         <script src="/bg/js/conditions.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/bg/js/options.js"></script>
         <script src="/bg/js/page-exit-prevention.js"></script>
         <script src="/bg/js/profile-conditions.js"></script>
-        <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/util.js"></script>
         <script src="/mixed/js/audio.js"></script>
 
diff --git a/ext/fg/float.html b/ext/fg/float.html
index bec5ae68..352a866a 100644
--- a/ext/fg/float.html
+++ b/ext/fg/float.html
@@ -35,7 +35,7 @@
                 <h1>Yomichan Updated!</h1>
                 <p>
                     The Yomichan extension has been updated to a new version! In order to continue
-                    viewing definitions on this page you must reload this tab or restart your browser.
+                    viewing definitions on this page, you must reload this tab or restart your browser.
                 </p>
             </div>
         </div>
@@ -51,6 +51,7 @@
         <script src="/mixed/js/display.js"></script>
         <script src="/mixed/js/display-generator.js"></script>
         <script src="/mixed/js/scroll.js"></script>
+        <script src="/mixed/js/template-handler.js"></script>
 
         <script src="/fg/js/float.js"></script>
 
diff --git a/ext/fg/js/document.js b/ext/fg/js/document.js
index 71654b29..35861475 100644
--- a/ext/fg/js/document.js
+++ b/ext/fg/js/document.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global TextSourceElement, TextSourceRange, DOM*/
 
 const REGEX_TRANSPARENT_COLOR = /rgba\s*\([^)]*,\s*0(?:\.0+)?\s*\)/;
 
@@ -49,7 +50,9 @@ function docImposterCreate(element, isTextarea) {
     const imposter = document.createElement('div');
     const imposterStyle = imposter.style;
 
-    imposter.innerText = element.value;
+    let value = element.value;
+    if (value.endsWith('\n')) { value += '\n'; }
+    imposter.textContent = value;
 
     for (let i = 0, ii = elementStyle.length; i < ii; ++i) {
         const property = elementStyle[i];
@@ -191,8 +194,7 @@ function docSentenceExtract(source, extent) {
             if (terminators.includes(c)) {
                 endPos = i + 1;
                 break;
-            }
-            else if (c in quotesBwd) {
+            } else if (c in quotesBwd) {
                 endPos = i;
                 break;
             }
diff --git a/ext/fg/js/float.js b/ext/fg/js/float.js
index 8d61d8f6..8f21a9c5 100644
--- a/ext/fg/js/float.js
+++ b/ext/fg/js/float.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global popupNestedInitialize, apiForward, apiGetMessageToken, Display*/
 
 class DisplayFloat extends Display {
     constructor() {
@@ -28,11 +29,33 @@ class DisplayFloat extends Display {
         };
 
         this._orphaned = false;
+        this._prepareInvoked = false;
+        this._messageToken = null;
+        this._messageTokenPromise = null;
 
         yomichan.on('orphaned', () => this.onOrphaned());
         window.addEventListener('message', (e) => this.onMessage(e), false);
     }
 
+    async prepare(options, popupInfo, url, childrenSupported, scale, uniqueId) {
+        if (this._prepareInvoked) { return; }
+        this._prepareInvoked = true;
+
+        await super.prepare(options);
+
+        const {id, depth, parentFrameId} = popupInfo;
+        this.optionsContext.depth = depth;
+        this.optionsContext.url = url;
+
+        if (childrenSupported) {
+            popupNestedInitialize(id, depth, parentFrameId, url);
+        }
+
+        this.setContentScale(scale);
+
+        apiForward('popupPrepareCompleted', {uniqueId});
+    }
+
     onError(error) {
         if (this._orphaned) {
             this.setContent('orphaned');
@@ -54,11 +77,23 @@ class DisplayFloat extends Display {
     }
 
     onMessage(e) {
-        const {action, params} = e.data;
-        const handler = DisplayFloat._messageHandlers.get(action);
-        if (typeof handler !== 'function') { return; }
-
-        handler(this, params);
+        const data = e.data;
+        if (typeof data !== 'object' || data === null) { return; } // Invalid data
+
+        const token = data.token;
+        if (typeof token !== 'string') { return; } // Invalid data
+
+        if (this._messageToken === null) {
+            // Async
+            this.getMessageToken()
+                .then(
+                    () => { this.handleAction(token, data); },
+                    () => {}
+                );
+        } else {
+            // Sync
+            this.handleAction(token, data);
+        }
     }
 
     onKeyDown(e) {
@@ -73,6 +108,30 @@ class DisplayFloat extends Display {
         return super.onKeyDown(e);
     }
 
+    async getMessageToken() {
+        // this._messageTokenPromise is used to ensure that only one call to apiGetMessageToken is made.
+        if (this._messageTokenPromise === null) {
+            this._messageTokenPromise = apiGetMessageToken();
+        }
+        const messageToken = await this._messageTokenPromise;
+        if (this._messageToken === null) {
+            this._messageToken = messageToken;
+        }
+        this._messageTokenPromise = null;
+    }
+
+    handleAction(token, {action, params}) {
+        if (token !== this._messageToken) {
+            // Invalid token
+            return;
+        }
+
+        const handler = DisplayFloat._messageHandlers.get(action);
+        if (typeof handler !== 'function') { return; }
+
+        handler(this, params);
+    }
+
     getOptionsContext() {
         return this.optionsContext;
     }
@@ -92,20 +151,6 @@ class DisplayFloat extends Display {
     setContentScale(scale) {
         document.body.style.fontSize = `${scale}em`;
     }
-
-    async initialize(options, popupInfo, url, childrenSupported, scale) {
-        await super.initialize(options);
-
-        const {id, depth, parentFrameId} = popupInfo;
-        this.optionsContext.depth = depth;
-        this.optionsContext.url = url;
-
-        if (childrenSupported) {
-            popupNestedInitialize(id, depth, parentFrameId, url);
-        }
-
-        this.setContentScale(scale);
-    }
 }
 
 DisplayFloat._onKeyDownHandlers = new Map([
@@ -122,7 +167,7 @@ DisplayFloat._messageHandlers = new Map([
     ['setContent', (self, {type, details}) => self.setContent(type, details)],
     ['clearAutoPlayTimer', (self) => self.clearAutoPlayTimer()],
     ['setCustomCss', (self, {css}) => self.setCustomCss(css)],
-    ['initialize', (self, {options, popupInfo, url, childrenSupported, scale}) => self.initialize(options, popupInfo, url, childrenSupported, scale)],
+    ['prepare', (self, {options, popupInfo, url, childrenSupported, scale, uniqueId}) => self.prepare(options, popupInfo, url, childrenSupported, scale, uniqueId)],
     ['setContentScale', (self, {scale}) => self.setContentScale(scale)]
 ]);
 
diff --git a/ext/fg/js/frontend-api-sender.js b/ext/fg/js/frontend-api-sender.js
index 93c2e593..8dc6aaf3 100644
--- a/ext/fg/js/frontend-api-sender.js
+++ b/ext/fg/js/frontend-api-sender.js
@@ -19,7 +19,7 @@
 
 class FrontendApiSender {
     constructor() {
-        this.senderId = FrontendApiSender.generateId(16);
+        this.senderId = yomichan.generateId(16);
         this.ackTimeout = 3000; // 3 seconds
         this.responseTimeout = 10000; // 10 seconds
         this.callbacks = new Map();
@@ -123,12 +123,4 @@ class FrontendApiSender {
         info.timer = null;
         info.reject(new Error(reason));
     }
-
-    static generateId(length) {
-        let id = '';
-        for (let i = 0; i < length; ++i) {
-            id += Math.floor(Math.random() * 256).toString(16).padStart(2, '0');
-        }
-        return id;
-    }
 }
diff --git a/ext/fg/js/frontend-initialize.js b/ext/fg/js/frontend-initialize.js
index 9c923fea..54b874f2 100644
--- a/ext/fg/js/frontend-initialize.js
+++ b/ext/fg/js/frontend-initialize.js
@@ -16,18 +16,22 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global PopupProxyHost, PopupProxy, Frontend*/
 
 async function main() {
     const data = window.frontendInitializationData || {};
     const {id, depth=0, parentFrameId, ignoreNodes, url, proxy=false} = data;
 
-    let popupHost = null;
-    if (!proxy) {
-        popupHost = new PopupProxyHost();
+    let popup;
+    if (proxy) {
+        popup = new PopupProxy(null, depth + 1, id, parentFrameId, url);
+    } else {
+        const popupHost = new PopupProxyHost();
         await popupHost.prepare();
+
+        popup = popupHost.getOrCreatePopup();
     }
 
-    const popup = proxy ? new PopupProxy(depth + 1, id, parentFrameId, url) : popupHost.createPopup(null, depth);
     const frontend = new Frontend(popup, ignoreNodes);
     await frontend.prepare();
 }
diff --git a/ext/fg/js/frontend.js b/ext/fg/js/frontend.js
index 2286bf19..67045241 100644
--- a/ext/fg/js/frontend.js
+++ b/ext/fg/js/frontend.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiGetZoom, apiOptionsGet, apiTermsFind, apiKanjiFind, docSentenceExtract, TextScanner*/
 
 class Frontend extends TextScanner {
     constructor(popup, ignoreNodes) {
@@ -55,7 +56,7 @@ class Frontend extends TextScanner {
             }
 
             yomichan.on('orphaned', () => this.onOrphaned());
-            yomichan.on('optionsUpdate', () => this.updateOptions());
+            yomichan.on('optionsUpdated', () => this.updateOptions());
             yomichan.on('zoomChanged', (e) => this.onZoomChanged(e));
             chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
 
diff --git a/ext/fg/js/popup-nested.js b/ext/fg/js/popup-nested.js
index 3f3c945e..3e5f5b80 100644
--- a/ext/fg/js/popup-nested.js
+++ b/ext/fg/js/popup-nested.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGet*/
 
 let popupNestedInitialized = false;
 
diff --git a/ext/fg/js/popup-proxy-host.js b/ext/fg/js/popup-proxy-host.js
index 427172c6..e55801ff 100644
--- a/ext/fg/js/popup-proxy-host.js
+++ b/ext/fg/js/popup-proxy-host.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiFrameInformationGet, FrontendApiReceiver, Popup*/
 
 class PopupProxyHost {
     constructor() {
@@ -33,7 +34,7 @@ class PopupProxyHost {
         if (typeof frameId !== 'number') { return; }
 
         this._apiReceiver = new FrontendApiReceiver(`popup-proxy-host#${frameId}`, new Map([
-            ['createNestedPopup', ({parentId}) => this._onApiCreateNestedPopup(parentId)],
+            ['getOrCreatePopup', ({id, parentId}) => this._onApiGetOrCreatePopup(id, parentId)],
             ['setOptions', ({id, options}) => this._onApiSetOptions(id, options)],
             ['hide', ({id, changeFocus}) => this._onApiHide(id, changeFocus)],
             ['isVisible', ({id}) => this._onApiIsVisibleAsync(id)],
@@ -46,14 +47,51 @@ class PopupProxyHost {
         ]));
     }
 
-    createPopup(parentId, depth) {
-        return this._createPopupInternal(parentId, depth).popup;
+    getOrCreatePopup(id=null, parentId=null) {
+        // Find by existing id
+        if (id !== null) {
+            const popup = this._popups.get(id);
+            if (typeof popup !== 'undefined') {
+                return popup;
+            }
+        }
+
+        // Find by existing parent id
+        let parent = null;
+        if (parentId !== null) {
+            parent = this._popups.get(parentId);
+            if (typeof parent !== 'undefined') {
+                const popup = parent.child;
+                if (popup !== null) {
+                    return popup;
+                }
+            } else {
+                parent = null;
+            }
+        }
+
+        // New unique id
+        if (id === null) {
+            id = this._nextId++;
+        }
+
+        // Create new popup
+        const depth = (parent !== null ? parent.depth + 1 : 0);
+        const popup = new Popup(id, depth, this._frameIdPromise);
+        if (parent !== null) {
+            popup.setParent(parent);
+        }
+        this._popups.set(id, popup);
+        return popup;
     }
 
     // Message handlers
 
-    async _onApiCreateNestedPopup(parentId) {
-        return this._createPopupInternal(parentId, 0).id;
+    async _onApiGetOrCreatePopup(id, parentId) {
+        const popup = this.getOrCreatePopup(id, parentId);
+        return {
+            id: popup.id
+        };
     }
 
     async _onApiSetOptions(id, options) {
@@ -105,25 +143,10 @@ class PopupProxyHost {
 
     // Private functions
 
-    _createPopupInternal(parentId, depth) {
-        const parent = (typeof parentId === 'string' && this._popups.has(parentId) ? this._popups.get(parentId) : null);
-        const id = `${this._nextId}`;
-        if (parent !== null) {
-            depth = parent.depth + 1;
-        }
-        ++this._nextId;
-        const popup = new Popup(id, depth, this._frameIdPromise);
-        if (parent !== null) {
-            popup.setParent(parent);
-        }
-        this._popups.set(id, popup);
-        return {popup, id};
-    }
-
     _getPopup(id) {
         const popup = this._popups.get(id);
         if (typeof popup === 'undefined') {
-            throw new Error('Invalid popup ID');
+            throw new Error(`Invalid popup ID ${id}`);
         }
         return popup;
     }
diff --git a/ext/fg/js/popup-proxy.js b/ext/fg/js/popup-proxy.js
index 4cacee53..093cdd2e 100644
--- a/ext/fg/js/popup-proxy.js
+++ b/ext/fg/js/popup-proxy.js
@@ -16,12 +16,13 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global FrontendApiSender*/
 
 class PopupProxy {
-    constructor(depth, parentId, parentFrameId, url) {
+    constructor(id, depth, parentId, parentFrameId, url) {
         this._parentId = parentId;
         this._parentFrameId = parentFrameId;
-        this._id = null;
+        this._id = id;
         this._idPromise = null;
         this._depth = depth;
         this._url = url;
@@ -69,7 +70,7 @@ class PopupProxy {
         if (this._id === null) {
             return;
         }
-        this._invokeHostApi('setVisibleOverride', {id, visible});
+        this._invokeHostApi('setVisibleOverride', {id: this._id, visible});
     }
 
     async containsPoint(x, y) {
@@ -112,7 +113,7 @@ class PopupProxy {
     }
 
     async _getPopupIdAsync() {
-        const id = await this._invokeHostApi('createNestedPopup', {parentId: this._parentId});
+        const {id} = await this._invokeHostApi('getOrCreatePopup', {id: this._id, parentId: this._parentId});
         this._id = id;
         return id;
     }
diff --git a/ext/fg/js/popup.js b/ext/fg/js/popup.js
index e7dae93e..4927f4bd 100644
--- a/ext/fg/js/popup.js
+++ b/ext/fg/js/popup.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiInjectStylesheet, apiGetMessageToken*/
 
 class Popup {
     constructor(id, depth, frameIdPromise) {
@@ -27,32 +28,40 @@ class Popup {
         this._child = null;
         this._childrenSupported = true;
         this._injectPromise = null;
-        this._isInjected = false;
-        this._isInjectedAndLoaded = false;
         this._visible = false;
         this._visibleOverride = null;
         this._options = null;
-        this._stylesheetInjectedViaApi = false;
         this._contentScale = 1.0;
         this._containerSizeContentScale = null;
+        this._targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
+        this._messageToken = null;
 
         this._container = document.createElement('iframe');
         this._container.className = 'yomichan-float';
         this._container.addEventListener('mousedown', (e) => e.stopPropagation());
         this._container.addEventListener('scroll', (e) => e.stopPropagation());
-        this._container.setAttribute('src', chrome.runtime.getURL('/fg/float.html'));
         this._container.style.width = '0px';
         this._container.style.height = '0px';
 
+        this._fullscreenEventListeners = new EventListenerCollection();
+
         this._updateVisibility();
     }
 
     // Public properties
 
+    get id() {
+        return this._id;
+    }
+
     get parent() {
         return this._parent;
     }
 
+    get child() {
+        return this._child;
+    }
+
     get depth() {
         return this._depth;
     }
@@ -117,16 +126,12 @@ class Popup {
     }
 
     clearAutoPlayTimer() {
-        if (this._isInjectedAndLoaded) {
-            this._invokeApi('clearAutoPlayTimer');
-        }
+        this._invokeApi('clearAutoPlayTimer');
     }
 
     setContentScale(scale) {
         this._contentScale = scale;
-        if (this._isInjectedAndLoaded) {
-            this._invokeApi('setContentScale', {scale});
-        }
+        this._invokeApi('setContentScale', {scale});
     }
 
     // Popup-only public functions
@@ -146,7 +151,7 @@ class Popup {
     }
 
     isVisibleSync() {
-        return this._isInjected && (this._visibleOverride !== null ? this._visibleOverride : this._visible);
+        return (this._visibleOverride !== null ? this._visibleOverride : this._visible);
     }
 
     updateTheme() {
@@ -154,21 +159,13 @@ class Popup {
         this._container.dataset.yomichanSiteColor = this._getSiteColor();
     }
 
-    async setCustomOuterCss(css, injectDirectly) {
-        // Cannot repeatedly inject stylesheets using web extension APIs since there is no way to remove them.
-        if (this._stylesheetInjectedViaApi) { return; }
-
-        if (injectDirectly || Popup._isOnExtensionPage()) {
-            Popup.injectOuterStylesheet(css);
-        } else {
-            if (!css) { return; }
-            try {
-                await apiInjectStylesheet(css);
-                this._stylesheetInjectedViaApi = true;
-            } catch (e) {
-                // NOP
-            }
-        }
+    async setCustomOuterCss(css, useWebExtensionApi) {
+        return await Popup._injectStylesheet(
+            'yomichan-popup-outer-user-stylesheet',
+            'code',
+            css,
+            useWebExtensionApi
+        );
     }
 
     setChildrenSupported(value) {
@@ -183,26 +180,6 @@ class Popup {
         return this._container.getBoundingClientRect();
     }
 
-    static injectOuterStylesheet(css) {
-        if (Popup.outerStylesheet === null) {
-            if (!css) { return; }
-            Popup.outerStylesheet = document.createElement('style');
-            Popup.outerStylesheet.id = 'yomichan-popup-outer-stylesheet';
-        }
-
-        const outerStylesheet = Popup.outerStylesheet;
-        if (css) {
-            outerStylesheet.textContent = css;
-
-            const par = document.head;
-            if (par && outerStylesheet.parentNode !== par) {
-                par.appendChild(outerStylesheet);
-            }
-        } else {
-            outerStylesheet.textContent = '';
-        }
-    }
-
     // Private functions
 
     _inject() {
@@ -222,11 +199,18 @@ class Popup {
             // NOP
         }
 
+        if (this._messageToken === null) {
+            this._messageToken = await apiGetMessageToken();
+        }
+
         return new Promise((resolve) => {
             const parentFrameId = (typeof this._frameId === 'number' ? this._frameId : null);
+            this._container.setAttribute('src', chrome.runtime.getURL('/fg/float.html'));
             this._container.addEventListener('load', () => {
-                this._isInjectedAndLoaded = true;
-                this._invokeApi('initialize', {
+                const uniqueId = yomichan.generateId(32);
+                Popup._listenForDisplayPrepareCompleted(uniqueId, resolve);
+
+                this._invokeApi('prepare', {
                     options: this._options,
                     popupInfo: {
                         id: this._id,
@@ -235,17 +219,60 @@ class Popup {
                     },
                     url: this.url,
                     childrenSupported: this._childrenSupported,
-                    scale: this._contentScale
+                    scale: this._contentScale,
+                    uniqueId
                 });
-                resolve();
             });
-            this._observeFullscreen();
+            this._observeFullscreen(true);
             this._onFullscreenChanged();
-            this.setCustomOuterCss(this._options.general.customPopupOuterCss, false);
-            this._isInjected = true;
+            this._injectStyles();
         });
     }
 
+    async _injectStyles() {
+        try {
+            await Popup._injectStylesheet('yomichan-popup-outer-stylesheet', 'file', '/fg/css/client.css', true);
+        } catch (e) {
+            // NOP
+        }
+
+        try {
+            await this.setCustomOuterCss(this._options.general.customPopupOuterCss, true);
+        } catch (e) {
+            // NOP
+        }
+    }
+
+    _observeFullscreen(observe) {
+        if (!observe) {
+            this._fullscreenEventListeners.removeAllEventListeners();
+            return;
+        }
+
+        if (this._fullscreenEventListeners.size > 0) {
+            // Already observing
+            return;
+        }
+
+        const fullscreenEvents = [
+            'fullscreenchange',
+            'MSFullscreenChange',
+            'mozfullscreenchange',
+            'webkitfullscreenchange'
+        ];
+        const onFullscreenChanged = () => this._onFullscreenChanged();
+        for (const eventName of fullscreenEvents) {
+            this._fullscreenEventListeners.addEventListener(document, eventName, onFullscreenChanged, false);
+        }
+    }
+
+    _onFullscreenChanged() {
+        const parent = (Popup._getFullscreenElement() || document.body || null);
+        if (parent !== null && this._container.parentNode !== parent) {
+            parent.appendChild(this._container);
+        }
+    }
+
     async _show(elementRect, writingMode) {
         await this._inject();
 
@@ -327,38 +354,38 @@ class Popup {
     }
 
     _invokeApi(action, params={}) {
-        if (!this._isInjectedAndLoaded) {
-            throw new Error('Frame not loaded');
-        }
-        this._container.contentWindow.postMessage({action, params}, '*');
-    }
+        const token = this._messageToken;
+        const contentWindow = this._container.contentWindow;
+        if (token === null || contentWindow === null) { return; }
 
-    _observeFullscreen() {
-        const fullscreenEvents = [
-            'fullscreenchange',
-            'MSFullscreenChange',
-            'mozfullscreenchange',
-            'webkitfullscreenchange'
-        ];
-        for (const eventName of fullscreenEvents) {
-            document.addEventListener(eventName, () => this._onFullscreenChanged(), false);
-        }
+        contentWindow.postMessage({action, params, token}, this._targetOrigin);
     }
 
-    _getFullscreenElement() {
+    static _getFullscreenElement() {
         return (
             document.fullscreenElement ||
             document.msFullscreenElement ||
             document.mozFullScreenElement ||
-            document.webkitFullscreenElement
+            document.webkitFullscreenElement ||
+            null
         );
     }
 
-    _onFullscreenChanged() {
-        const parent = (this._getFullscreenElement() || document.body || null);
-        if (parent !== null && this._container.parentNode !== parent) {
-            parent.appendChild(this._container);
-        }
+    static _listenForDisplayPrepareCompleted(uniqueId, resolve) {
+        const runtimeMessageCallback = ({action, params}, sender, callback) => {
+            if (
+                action === 'popupPrepareCompleted' &&
+                typeof params === 'object' &&
+                params !== null &&
+                params.uniqueId === uniqueId
+            ) {
+                chrome.runtime.onMessage.removeListener(runtimeMessageCallback);
+                callback();
+                resolve();
+                return false;
+            }
+        };
+        chrome.runtime.onMessage.addListener(runtimeMessageCallback);
     }
 
     static _getPositionForHorizontalText(elementRect, width, height, viewport, offsetScale, optionsGeneral) {
@@ -492,15 +519,6 @@ class Popup {
         ];
     }
 
-    static _isOnExtensionPage() {
-        try {
-            const url = chrome.runtime.getURL('/');
-            return window.location.href.substring(0, url.length) === url;
-        } catch (e) {
-            // NOP
-        }
-    }
-
     static _getViewport(useVisualViewport) {
         const visualViewport = window.visualViewport;
         if (visualViewport !== null && typeof visualViewport === 'object') {
@@ -533,6 +551,80 @@ class Popup {
             bottom: window.innerHeight
         };
     }
+
+    static _isOnExtensionPage() {
+        try {
+            const url = chrome.runtime.getURL('/');
+            return window.location.href.substring(0, url.length) === url;
+        } catch (e) {
+            // NOP
+        }
+    }
+
+    static async _injectStylesheet(id, type, value, useWebExtensionApi) {
+        const injectedStylesheets = Popup._injectedStylesheets;
+
+        if (Popup._isOnExtensionPage()) {
+            // Permissions error will occur if trying to use the WebExtension API to inject
+            // into an extension page.
+            useWebExtensionApi = false;
+        }
+
+        let styleNode = injectedStylesheets.get(id);
+        if (typeof styleNode !== 'undefined') {
+            if (styleNode === null) {
+                // Previously injected via WebExtension API
+                throw new Error(`Stylesheet with id ${id} has already been injected using the WebExtension API`);
+            }
+        } else {
+            styleNode = null;
+        }
+
+        if (useWebExtensionApi) {
+            // Inject via WebExtension API
+            if (styleNode !== null && styleNode.parentNode !== null) {
+                styleNode.parentNode.removeChild(styleNode);
+            }
+
+            await apiInjectStylesheet(type, value);
+
+            injectedStylesheets.set(id, null);
+            return null;
+        }
+
+        // Create node in document
+        const parentNode = document.head;
+        if (parentNode === null) {
+            throw new Error('No parent node');
+        }
+
+        // Create or reuse node
+        const isFile = (type === 'file');
+        const tagName = isFile ? 'link' : 'style';
+        if (styleNode === null || styleNode.nodeName.toLowerCase() !== tagName) {
+            if (styleNode !== null && styleNode.parentNode !== null) {
+                styleNode.parentNode.removeChild(styleNode);
+            }
+            styleNode = document.createElement(tagName);
+            styleNode.id = id;
+        }
+
+        // Update node style
+        if (isFile) {
+            styleNode.rel = value;
+        } else {
+            styleNode.textContent = value;
+        }
+
+        // Update parent
+        if (styleNode.parentNode !== parentNode) {
+            parentNode.appendChild(styleNode);
+        }
+
+        // Add to map
+        injectedStylesheets.set(id, styleNode);
+        return styleNode;
+    }
 }
 
-Popup.outerStylesheet = null;
+Popup._injectedStylesheets = new Map();
diff --git a/ext/fg/js/source.js b/ext/fg/js/source.js
index 11d3ff0e..6dc482bd 100644
--- a/ext/fg/js/source.js
+++ b/ext/fg/js/source.js
@@ -82,7 +82,11 @@ class TextSourceRange {
     }
 
     equals(other) {
-        if (other === null) {
+        if (!(
+            typeof other === 'object' &&
+            other !== null &&
+            other instanceof TextSourceRange
+        )) {
             return false;
         }
         if (this.imposterSourceElement !== null) {
@@ -362,7 +366,7 @@ class TextSourceElement {
     setEndOffset(length) {
         switch (this.element.nodeName.toUpperCase()) {
             case 'BUTTON':
-                this.content = this.element.innerHTML;
+                this.content = this.element.textContent;
                 break;
             case 'IMG':
                 this.content = this.element.getAttribute('alt');
@@ -409,6 +413,12 @@ class TextSourceElement {
     }
 
     equals(other) {
-        return other && other.element === this.element && other.content === this.content;
+        return (
+            typeof other === 'object' &&
+            other !== null &&
+            other instanceof TextSourceElement &&
+            other.element === this.element &&
+            other.content === this.content
+        );
     }
 }
diff --git a/ext/manifest.json b/ext/manifest.json
index 31729992..fd9b6fec 100644
--- a/ext/manifest.json
+++ b/ext/manifest.json
@@ -1,7 +1,7 @@
 {
     "manifest_version": 2,
     "name": "Yomichan (testing)",
-    "version": "20.1.26.0",
+    "version": "20.2.24.0",
 
     "description": "Japanese dictionary with Anki integration (testing)",
     "icons": {"16": "mixed/img/icon16.png", "48": "mixed/img/icon48.png", "128": "mixed/img/icon128.png"},
@@ -30,7 +30,7 @@
             "fg/js/frontend.js",
             "fg/js/frontend-initialize.js"
         ],
-        "css": ["fg/css/client.css"],
+        "match_about_blank": true,
         "all_frames": true
     }],
     "minimum_chrome_version": "57.0.0.0",
diff --git a/ext/mixed/css/display-dark.css b/ext/mixed/css/display-dark.css
index 088fc741..c9cd9f90 100644
--- a/ext/mixed/css/display-dark.css
+++ b/ext/mixed/css/display-dark.css
@@ -38,6 +38,7 @@ body { background-color: #1e1e1e; color: #d4d4d4; }
 .tag[data-category=dictionary]   { background-color: #9057ad; }
 .tag[data-category=frequency]    { background-color: #489148; }
 .tag[data-category=partOfSpeech] { background-color: #565656; }
+.tag[data-category=search]       { background-color: #69696e; }
 
 .term-reasons { color: #888888; }
 
diff --git a/ext/mixed/css/display-default.css b/ext/mixed/css/display-default.css
index 69141c9d..6eee43c4 100644
--- a/ext/mixed/css/display-default.css
+++ b/ext/mixed/css/display-default.css
@@ -38,6 +38,7 @@ body { background-color: #ffffff; color: #333333; }
 .tag[data-category=dictionary]   { background-color: #aa66cc; }
 .tag[data-category=frequency]    { background-color: #5cb85c; }
 .tag[data-category=partOfSpeech] { background-color: #565656; }
+.tag[data-category=search]       { background-color: #8a8a91; }
 
 .term-reasons { color: #777777; }
 
diff --git a/ext/mixed/css/display.css b/ext/mixed/css/display.css
index add2583e..6a5383bc 100644
--- a/ext/mixed/css/display.css
+++ b/ext/mixed/css/display.css
@@ -127,15 +127,19 @@ html:root[data-yomichan-page=float] .navigation-header:not([hidden])~.navigation
     user-select: none;
 }
 
-#query-parser {
+#query-parser-content {
     margin-top: 0.5em;
     font-size: 2em;
 }
 
-#query-parser[data-term-spacing=true] .query-parser-term {
+#query-parser-content[data-term-spacing=true] .query-parser-term {
     margin-right: 0.2em;
 }
 
+html:root[data-yomichan-page=search][data-search-mode=popup] .search-input {
+    display: none;
+}
+
 
 /*
  * Entries
@@ -208,19 +212,27 @@ button.action-button {
 }
 
 .tag {
-    display: inline;
+    display: inline-block;
     padding: 0.2em 0.6em 0.3em;
     font-size: 75%;
     font-weight: 700;
-    line-height: 1;
+    line-height: 1.25;
     text-align: center;
     white-space: nowrap;
     vertical-align: baseline;
     border-radius: 0.25em;
 }
 
-.tag-list>.tag+.tag {
-    margin-left: 0.375em;
+.tag-inner {
+    display: block;
+}
+
+.tag-list>.tag:not(:last-child) {
+    margin-right: 0.375em;
+}
+
+html:root:not([data-enable-search-tags=true]) .tag[data-category=search] {
+    display: none;
 }
 
 .entry-header2,
@@ -237,7 +249,7 @@ button.action-button {
     border-top-style: solid;
 }
 
-.entry[data-type=term][data-expression-multi=true]:not([data-expression-count="1"]) .actions>.action-play-audio {
+.entry[data-type=term][data-expression-multi=true] .actions>.action-play-audio {
     display: none;
 }
 
@@ -245,8 +257,9 @@ button.action-button {
     display: inline-block;
 }
 
-.term-reasons>.term-reason+.term-reason:before {
+.term-reasons>.term-reason+.term-reason-separator+.term-reason:before {
     content: " \00AB  "; /* The two spaces is not a typo */
+    white-space: pre-wrap;
     display: inline;
 }
 
@@ -284,13 +297,13 @@ button.action-button {
     content: "\3001";
 }
 
-.term-expression-list>.term-expression:last-of-type:not(:first-of-type):after {
+.term-expression-list[data-multi=true]>.term-expression:last-of-type:after {
     font-size: 2em;
     content: "\3000";
     visibility: hidden;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression-details {
+.term-expression-list[data-multi=true] .term-expression-details {
     display: inline-block;
     position: relative;
     width: 0;
@@ -298,21 +311,21 @@ button.action-button {
     visibility: hidden;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression:hover .term-expression-details {
+.term-expression-list[data-multi=true] .term-expression:hover .term-expression-details {
     visibility: visible;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression-details>.action-play-audio {
+.term-expression-list[data-multi=true] .term-expression-details>.action-play-audio {
     position: absolute;
     left: 0;
     bottom: 0.5em;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression-details>.action-play-audio {
+.term-expression-list[data-multi=true] .term-expression-details>.action-play-audio {
     display: block;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression-details>.tags {
+.term-expression-list[data-multi=true] .term-expression-details>.tags {
     display: block;
     position: absolute;
     left: 0;
@@ -320,7 +333,7 @@ button.action-button {
     white-space: nowrap;
 }
 
-.term-expression-list[data-multi=true]:not([data-count="1"]) .term-expression-details>.frequencies {
+.term-expression-list[data-multi=true] .term-expression-details>.frequencies {
     display: block;
     position: absolute;
     left: 0;
@@ -385,7 +398,7 @@ button.action-button {
 
 :root[data-compact-glossaries=true] .term-definition-tag-list,
 :root[data-compact-glossaries=true] .term-definition-only-list:not([data-count="0"]) {
-    display: inline-block;
+    display: inline;
 }
 
 :root[data-compact-glossaries=true] .term-glossary-list {
@@ -399,9 +412,24 @@ button.action-button {
 }
 
 :root[data-compact-glossaries=true] .term-glossary-list>li:not(:first-child):before {
+    white-space: pre-wrap;
     content: " | ";
+    display: inline;
 }
 
+.term-glossary-separator,
+.term-reason-separator {
+    display: inline;
+    font-size: 0;
+    opacity: 0;
+    white-space: pre-wrap;
+}
+
+.term-special-tags>.frequencies {
+    display: inline;
+}
+
+
 /*
  * Kanji
  */
diff --git a/ext/mixed/display-templates.html b/ext/mixed/display-templates.html
index 62f3c69c..7ae51a62 100644
--- a/ext/mixed/display-templates.html
+++ b/ext/mixed/display-templates.html
@@ -15,7 +15,7 @@
             </div>
             <div class="term-reasons"></div>
         </div>
-        <div class="frequencies"></div>
+        <div class="term-special-tags"><div class="frequencies tag-list"></div></div>
     </div>
     <div class="term-definition-container"><ol class="term-definition-list"></ol></div>
     <pre class="debug-info"></pre>
@@ -31,8 +31,8 @@
     <ul class="term-glossary-list"></ul>
 </li></template>
 <template id="term-definition-only-template"><span class="term-definition-only"></span></template>
-<template id="term-glossary-item-template"><li class="term-glossary-item"><span class="term-glossary"></span></li></template>
-<template id="term-reason-template"><span class="term-reason"></span></template>
+<template id="term-glossary-item-template"><li class="term-glossary-item"><span class="term-glossary-separator"> </span><span class="term-glossary"></span></li></template>
+<template id="term-reason-template"><span class="term-reason"></span><span class="term-reason-separator"> </span></template>
 
 <template id="kanji-entry-template"><div class="entry" data-type="kanji">
     <div class="entry-header1">
@@ -75,7 +75,8 @@
 <template id="kanji-glossary-item-template"><li class="kanji-glossary-item"><span class="kanji-glossary"></span></li></template>
 <template id="kanji-reading-template"><dd class="kanji-reading"></dd></template>
 
-<template id="tag-template"><span class="tag"></span></template>
-<template id="tag-frequency-template"><span class="tag" data-category="frequency"><span class="term-frequency-dictionary-name"></span><span class="term-frequency-separator"></span><span class="term-frequency-value"></span></template>
+<template id="tag-template"><span class="tag"><span class="tag-inner"></span></span></template>
+<template id="tag-frequency-template"><span class="tag" data-category="frequency"><span class="tag-inner"><span class="term-frequency-dictionary-name"></span><span class="term-frequency-separator"></span><span class="term-frequency-value"></span></span></template>
+<template id="tag-search-template"><span class="tag" data-category="search"></span></template>
 
 </body></html>
diff --git a/ext/mixed/js/api.js b/ext/mixed/js/api.js
index 5ec93b01..7ea68d59 100644
--- a/ext/mixed/js/api.js
+++ b/ext/mixed/js/api.js
@@ -58,15 +58,15 @@ function apiDefinitionAdd(definition, mode, context, optionsContext) {
 }
 
 function apiDefinitionsAddable(definitions, modes, optionsContext) {
-    return _apiInvoke('definitionsAddable', {definitions, modes, optionsContext}).catch(() => null);
+    return _apiInvoke('definitionsAddable', {definitions, modes, optionsContext});
 }
 
 function apiNoteView(noteId) {
     return _apiInvoke('noteView', {noteId});
 }
 
-function apiTemplateRender(template, data, dynamic) {
-    return _apiInvoke('templateRender', {data, template, dynamic});
+function apiTemplateRender(template, data) {
+    return _apiInvoke('templateRender', {data, template});
 }
 
 function apiAudioGetUrl(definition, source, optionsContext) {
@@ -89,8 +89,8 @@ function apiFrameInformationGet() {
     return _apiInvoke('frameInformationGet');
 }
 
-function apiInjectStylesheet(css) {
-    return _apiInvoke('injectStylesheet', {css});
+function apiInjectStylesheet(type, value) {
+    return _apiInvoke('injectStylesheet', {type, value});
 }
 
 function apiGetEnvironmentInfo() {
@@ -105,10 +105,18 @@ function apiGetDisplayTemplatesHtml() {
     return _apiInvoke('getDisplayTemplatesHtml');
 }
 
+function apiGetQueryParserTemplatesHtml() {
+    return _apiInvoke('getQueryParserTemplatesHtml');
+}
+
 function apiGetZoom() {
     return _apiInvoke('getZoom');
 }
 
+function apiGetMessageToken() {
+    return _apiInvoke('getMessageToken');
+}
+
 function _apiInvoke(action, params={}) {
     const data = {action, params};
     return new Promise((resolve, reject) => {
diff --git a/ext/mixed/js/audio.js b/ext/mixed/js/audio.js
index b0c5fa82..b5a025be 100644
--- a/ext/mixed/js/audio.js
+++ b/ext/mixed/js/audio.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiAudioGetUrl*/
 
 class TextToSpeechAudio {
     constructor(text, voice) {
@@ -53,7 +54,6 @@ class TextToSpeechAudio {
 
             speechSynthesis.cancel();
             speechSynthesis.speak(this._utterance);
-
         } catch (e) {
             // NOP
         }
@@ -71,21 +71,16 @@ class TextToSpeechAudio {
         const m = /^tts:[^#?]*\?([^#]*)/.exec(ttsUri);
         if (m === null) { return null; }
 
-        const searchParameters = {};
-        for (const group of m[1].split('&')) {
-            const sep = group.indexOf('=');
-            if (sep < 0) { continue; }
-            searchParameters[decodeURIComponent(group.substring(0, sep))] = decodeURIComponent(group.substring(sep + 1));
-        }
-
-        if (!searchParameters.text) { return null; }
+        const searchParameters = new URLSearchParams(m[1]);
+        const text = searchParameters.get('text');
+        let voice = searchParameters.get('voice');
+        if (text === null || voice === null) { return null; }
 
-        const voice = audioGetTextToSpeechVoice(searchParameters.voice);
+        voice = audioGetTextToSpeechVoice(voice);
         if (voice === null) { return null; }
 
-        return new TextToSpeechAudio(searchParameters.text, voice);
+        return new TextToSpeechAudio(text, voice);
     }
-
 }
 
 function audioGetFromUrl(url, willDownload) {
@@ -113,8 +108,11 @@ function audioGetFromUrl(url, willDownload) {
 
 async function audioGetFromSources(expression, sources, optionsContext, willDownload, cache=null) {
     const key = `${expression.expression}:${expression.reading}`;
-    if (cache !== null && hasOwn(cache, expression)) {
-        return cache[key];
+    if (cache !== null) {
+        const cacheValue = cache.get(expression);
+        if (typeof cacheValue !== 'undefined') {
+            return cacheValue;
+        }
     }
 
     for (let i = 0, ii = sources.length; i < ii; ++i) {
@@ -132,7 +130,7 @@ async function audioGetFromSources(expression, sources, optionsContext, willDown
             }
             const result = {audio, url, source};
             if (cache !== null) {
-                cache[key] = result;
+                cache.set(key, result);
             }
             return result;
         } catch (e) {
diff --git a/ext/mixed/js/core.js b/ext/mixed/js/core.js
index 0142d594..83813796 100644
--- a/ext/mixed/js/core.js
+++ b/ext/mixed/js/core.js
@@ -113,11 +113,7 @@ function toIterable(value) {
     if (value !== null && typeof value === 'object') {
         const length = value.length;
         if (typeof length === 'number' && Number.isFinite(length)) {
-            const array = [];
-            for (let i = 0; i < length; ++i) {
-                array.push(value[i]);
-            }
-            return array;
+            return Array.from(value);
         }
     }
 
@@ -128,6 +124,14 @@ function stringReverse(string) {
     return string.split('').reverse().join('').replace(/([\uDC00-\uDFFF])([\uD800-\uDBFF])/g, '$2$1');
 }
 
+function parseUrl(url) {
+    const parsedUrl = new URL(url);
+    const baseUrl = `${parsedUrl.origin}${parsedUrl.pathname}`;
+    const queryParams = Array.from(parsedUrl.searchParams.entries())
+        .reduce((a, [k, v]) => Object.assign({}, a, {[k]: v}), {});
+    return {baseUrl, queryParams};
+}
+
 
 /*
  * Async utilities
@@ -156,9 +160,9 @@ function promiseTimeout(delay, resolveValue) {
     const resolve = (value) => complete(promiseResolve, value);
     const reject = (value) => complete(promiseReject, value);
 
-    const promise = new Promise((resolve, reject) => {
-        promiseResolve = resolve;
-        promiseReject = reject;
+    const promise = new Promise((resolve2, reject2) => {
+        promiseResolve = resolve2;
+        promiseReject = reject2;
     });
     timer = window.setTimeout(() => {
         timer = null;
@@ -232,6 +236,29 @@ class EventDispatcher {
     }
 }
 
+class EventListenerCollection {
+    constructor() {
+        this._eventListeners = [];
+    }
+
+    get size() {
+        return this._eventListeners.length;
+    }
+
+    addEventListener(node, type, listener, options) {
+        node.addEventListener(type, listener, options);
+        this._eventListeners.push([node, type, listener, options]);
+    }
+
+    removeAllEventListeners() {
+        if (this._eventListeners.length === 0) { return; }
+        for (const [node, type, listener, options] of this._eventListeners) {
+            node.removeEventListener(type, listener, options);
+        }
+        this._eventListeners = [];
+    }
+}
+
 
 /*
  * Default message handlers
@@ -244,7 +271,7 @@ const yomichan = (() => {
 
             this._messageHandlers = new Map([
                 ['getUrl', this._onMessageGetUrl.bind(this)],
-                ['optionsUpdate', this._onMessageOptionsUpdate.bind(this)],
+                ['optionsUpdated', this._onMessageOptionsUpdated.bind(this)],
                 ['zoomChanged', this._onMessageZoomChanged.bind(this)]
             ]);
 
@@ -253,6 +280,16 @@ const yomichan = (() => {
 
         // Public
 
+        generateId(length) {
+            const array = new Uint8Array(length);
+            window.crypto.getRandomValues(array);
+            let id = '';
+            for (const value of array) {
+                id += value.toString(16).padStart(2, '0');
+            }
+            return id;
+        }
+
         triggerOrphaned(error) {
             this.trigger('orphaned', {error});
         }
@@ -272,8 +309,8 @@ const yomichan = (() => {
             return {url: window.location.href};
         }
 
-        _onMessageOptionsUpdate({source}) {
-            this.trigger('optionsUpdate', {source});
+        _onMessageOptionsUpdated({source}) {
+            this.trigger('optionsUpdated', {source});
         }
 
         _onMessageZoomChanged({oldZoomFactor, newZoomFactor}) {
diff --git a/ext/mixed/js/display-generator.js b/ext/mixed/js/display-generator.js
index e1710488..d7e77cc0 100644
--- a/ext/mixed/js/display-generator.js
+++ b/ext/mixed/js/display-generator.js
@@ -16,46 +16,20 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*global apiGetDisplayTemplatesHtml, TemplateHandler*/
 
 class DisplayGenerator {
     constructor() {
-        this._isInitialized = false;
-        this._initializationPromise = null;
-
-        this._termEntryTemplate = null;
-        this._termExpressionTemplate = null;
-        this._termDefinitionItemTemplate = null;
-        this._termDefinitionOnlyTemplate = null;
-        this._termGlossaryItemTemplate = null;
-        this._termReasonTemplate = null;
-
-        this._kanjiEntryTemplate = null;
-        this._kanjiInfoTableTemplate = null;
-        this._kanjiInfoTableItemTemplate = null;
-        this._kanjiInfoTableEmptyTemplate = null;
-        this._kanjiGlossaryItemTemplate = null;
-        this._kanjiReadingTemplate = null;
-
-        this._tagTemplate = null;
-        this._tagFrequencyTemplate = null;
+        this._templateHandler = null;
     }
 
-    isInitialized() {
-        return this._isInitialized;
-    }
-
-    initialize() {
-        if (this._isInitialized) {
-            return Promise.resolve();
-        }
-        if (this._initializationPromise === null) {
-            this._initializationPromise = this._initializeInternal();
-        }
-        return this._initializationPromise;
+    async prepare() {
+        const html = await apiGetDisplayTemplatesHtml();
+        this._templateHandler = new TemplateHandler(html);
     }
 
     createTermEntry(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._termEntryTemplate);
+        const node = this._templateHandler.instantiate('term-entry');
 
         const expressionsContainer = node.querySelector('.term-expression-list');
         const reasonsContainer = node.querySelector('.term-reasons');
@@ -71,7 +45,11 @@ class DisplayGenerator {
         node.dataset.expressionCount = `${expressionMulti ? details.expressions.length : 1}`;
         node.dataset.definitionCount = `${definitionMulti ? details.definitions.length : 1}`;
 
-        DisplayGenerator._appendMultiple(expressionsContainer, this.createTermExpression.bind(this), details.expressions, [details]);
+        const termTags = details.termTags;
+        let expressions = details.expressions;
+        expressions = Array.isArray(expressions) ? expressions.map((e) => [e, termTags]) : null;
+
+        DisplayGenerator._appendMultiple(expressionsContainer, this.createTermExpression.bind(this), expressions, [[details, termTags]]);
         DisplayGenerator._appendMultiple(reasonsContainer, this.createTermReason.bind(this), details.reasons);
         DisplayGenerator._appendMultiple(frequenciesContainer, this.createFrequencyTag.bind(this), details.frequencies);
         DisplayGenerator._appendMultiple(definitionsContainer, this.createTermDefinitionItem.bind(this), details.definitions, [details]);
@@ -83,8 +61,8 @@ class DisplayGenerator {
         return node;
     }
 
-    createTermExpression(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._termExpressionTemplate);
+    createTermExpression([details, termTags]) {
+        const node = this._templateHandler.instantiate('term-expression');
 
         const expressionContainer = node.querySelector('.term-expression-text');
         const tagContainer = node.querySelector('.tags');
@@ -103,21 +81,30 @@ class DisplayGenerator {
             DisplayGenerator._appendFurigana(expressionContainer, furiganaSegments, this._appendKanjiLinks.bind(this));
         }
 
-        DisplayGenerator._appendMultiple(tagContainer, this.createTag.bind(this), details.termTags);
+        if (!Array.isArray(termTags)) {
+            // Fallback
+            termTags = details.termTags;
+        }
+        const searchQueries = [details.expression, details.reading]
+            .filter((x) => !!x)
+            .map((x) => ({query: x}));
+        DisplayGenerator._appendMultiple(tagContainer, this.createTag.bind(this), termTags);
+        DisplayGenerator._appendMultiple(tagContainer, this.createSearchTag.bind(this), searchQueries);
         DisplayGenerator._appendMultiple(frequencyContainer, this.createFrequencyTag.bind(this), details.frequencies);
 
         return node;
     }
 
     createTermReason(reason) {
-        const node = DisplayGenerator._instantiateTemplate(this._termReasonTemplate);
+        const fragment = this._templateHandler.instantiateFragment('term-reason');
+        const node = fragment.querySelector('.term-reason');
         node.textContent = reason;
         node.dataset.reason = reason;
-        return node;
+        return fragment;
     }
 
     createTermDefinitionItem(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._termDefinitionItemTemplate);
+        const node = this._templateHandler.instantiate('term-definition-item');
 
         const tagListContainer = node.querySelector('.term-definition-tag-list');
         const onlyListContainer = node.querySelector('.term-definition-only-list');
@@ -133,7 +120,7 @@ class DisplayGenerator {
     }
 
     createTermGlossaryItem(glossary) {
-        const node = DisplayGenerator._instantiateTemplate(this._termGlossaryItemTemplate);
+        const node = this._templateHandler.instantiate('term-glossary-item');
         const container = node.querySelector('.term-glossary');
         if (container !== null) {
             DisplayGenerator._appendMultilineText(container, glossary);
@@ -142,7 +129,7 @@ class DisplayGenerator {
     }
 
     createTermOnly(only) {
-        const node = DisplayGenerator._instantiateTemplate(this._termDefinitionOnlyTemplate);
+        const node = this._templateHandler.instantiate('term-definition-only');
         node.dataset.only = only;
         node.textContent = only;
         return node;
@@ -157,7 +144,7 @@ class DisplayGenerator {
     }
 
     createKanjiEntry(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._kanjiEntryTemplate);
+        const node = this._templateHandler.instantiate('kanji-entry');
 
         const glyphContainer = node.querySelector('.kanji-glyph');
         const frequenciesContainer = node.querySelector('.frequencies');
@@ -202,7 +189,7 @@ class DisplayGenerator {
     }
 
     createKanjiGlossaryItem(glossary) {
-        const node = DisplayGenerator._instantiateTemplate(this._kanjiGlossaryItemTemplate);
+        const node = this._templateHandler.instantiate('kanji-glossary-item');
         const container = node.querySelector('.kanji-glossary');
         if (container !== null) {
             DisplayGenerator._appendMultilineText(container, glossary);
@@ -211,13 +198,13 @@ class DisplayGenerator {
     }
 
     createKanjiReading(reading) {
-        const node = DisplayGenerator._instantiateTemplate(this._kanjiReadingTemplate);
+        const node = this._templateHandler.instantiate('kanji-reading');
         node.textContent = reading;
         return node;
     }
 
     createKanjiInfoTable(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._kanjiInfoTableTemplate);
+        const node = this._templateHandler.instantiate('kanji-info-table');
 
         const container = node.querySelector('.kanji-info-table-body');
 
@@ -233,7 +220,7 @@ class DisplayGenerator {
     }
 
     createKanjiInfoTableItem(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._kanjiInfoTableItemTemplate);
+        const node = this._templateHandler.instantiate('kanji-info-table-item');
         const nameNode = node.querySelector('.kanji-info-table-item-header');
         const valueNode = node.querySelector('.kanji-info-table-item-value');
         if (nameNode !== null) {
@@ -246,21 +233,33 @@ class DisplayGenerator {
     }
 
     createKanjiInfoTableItemEmpty() {
-        return DisplayGenerator._instantiateTemplate(this._kanjiInfoTableEmptyTemplate);
+        return this._templateHandler.instantiate('kanji-info-table-empty');
     }
 
     createTag(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._tagTemplate);
+        const node = this._templateHandler.instantiate('tag');
+
+        const inner = node.querySelector('.tag-inner');
 
         node.title = details.notes;
-        node.textContent = details.name;
+        inner.textContent = details.name;
         node.dataset.category = details.category;
 
         return node;
     }
 
+    createSearchTag(details) {
+        const node = this._templateHandler.instantiate('tag-search');
+
+        node.textContent = details.query;
+
+        node.dataset.query = details.query;
+
+        return node;
+    }
+
     createFrequencyTag(details) {
-        const node = DisplayGenerator._instantiateTemplate(this._tagFrequencyTemplate);
+        const node = this._templateHandler.instantiate('tag-frequency');
 
         let n = node.querySelector('.term-frequency-dictionary-name');
         if (n !== null) {
@@ -278,31 +277,6 @@ class DisplayGenerator {
         return node;
     }
 
-    async _initializeInternal() {
-        const html = await apiGetDisplayTemplatesHtml();
-        const doc = new DOMParser().parseFromString(html, 'text/html');
-        this._setTemplates(doc);
-    }
-
-    _setTemplates(doc) {
-        this._termEntryTemplate = doc.querySelector('#term-entry-template');
-        this._termExpressionTemplate = doc.querySelector('#term-expression-template');
-        this._termDefinitionItemTemplate = doc.querySelector('#term-definition-item-template');
-        this._termDefinitionOnlyTemplate = doc.querySelector('#term-definition-only-template');
-        this._termGlossaryItemTemplate = doc.querySelector('#term-glossary-item-template');
-        this._termReasonTemplate = doc.querySelector('#term-reason-template');
-
-        this._kanjiEntryTemplate = doc.querySelector('#kanji-entry-template');
-        this._kanjiInfoTableTemplate = doc.querySelector('#kanji-info-table-template');
-        this._kanjiInfoTableItemTemplate = doc.querySelector('#kanji-info-table-item-template');
-        this._kanjiInfoTableEmptyTemplate = doc.querySelector('#kanji-info-table-empty-template');
-        this._kanjiGlossaryItemTemplate = doc.querySelector('#kanji-glossary-item-template');
-        this._kanjiReadingTemplate = doc.querySelector('#kanji-reading-template');
-
-        this._tagTemplate = doc.querySelector('#tag-template');
-        this._tagFrequencyTemplate = doc.querySelector('#tag-frequency-template');
-    }
-
     _appendKanjiLinks(container, text) {
         let part = '';
         for (const c of text) {
@@ -372,8 +346,4 @@ class DisplayGenerator {
             container.appendChild(document.createTextNode(parts[i]));
         }
     }
-
-    static _instantiateTemplate(template) {
-        return document.importNode(template.content.firstChild, true);
-    }
 }
diff --git a/ext/mixed/js/display.js b/ext/mixed/js/display.js
index c4be02f2..5d3076ee 100644
--- a/ext/mixed/js/display.js
+++ b/ext/mixed/js/display.js
@@ -16,6 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global docRangeFromPoint, docSentenceExtract
+apiKanjiFind, apiTermsFind, apiNoteView, apiOptionsGet, apiDefinitionsAddable, apiDefinitionAdd
+apiScreenshotGet, apiForward
+audioPrepareTextToSpeech, audioGetFromSources
+DisplayGenerator, WindowScroll, DisplayContext, DOM*/
 
 class Display {
     constructor(spinner, container) {
@@ -27,11 +32,11 @@ class Display {
         this.index = 0;
         this.audioPlaying = null;
         this.audioFallback = null;
-        this.audioCache = {};
+        this.audioCache = new Map();
         this.styleNode = null;
 
-        this.eventListeners = [];
-        this.persistentEventListeners = [];
+        this.eventListeners = new EventListenerCollection();
+        this.persistentEventListeners = new EventListenerCollection();
         this.interactive = false;
         this.eventListenersActive = false;
         this.clickScanPrevent = false;
@@ -43,6 +48,13 @@ class Display {
         this.setInteractive(true);
     }
 
+    async prepare(options=null) {
+        const displayGeneratorPromise = this.displayGenerator.prepare();
+        const updateOptionsPromise = this.updateOptions(options);
+        await Promise.all([displayGeneratorPromise, updateOptionsPromise]);
+        yomichan.on('optionsUpdated', () => this.updateOptions(null));
+    }
+
     onError(_error) {
         throw new Error('Override me');
     }
@@ -174,15 +186,24 @@ class Display {
         e.preventDefault();
         const link = e.currentTarget;
         const entry = link.closest('.entry');
-        const definitionIndex = this.entryIndexFind(entry);
+        const index = this.entryIndexFind(entry);
+        if (index < 0 || index >= this.definitions.length) { return; }
+
         const expressionIndex = Display.indexOf(entry.querySelectorAll('.term-expression .action-play-audio'), link);
-        this.audioPlay(this.definitions[definitionIndex], expressionIndex, definitionIndex);
+        this.audioPlay(
+            this.definitions[index],
+            // expressionIndex is used in audioPlay to detect result output mode
+            Math.max(expressionIndex, this.options.general.resultOutputMode === 'merge' ? 0 : -1),
+            index
+        );
     }
 
     onNoteAdd(e) {
         e.preventDefault();
         const link = e.currentTarget;
         const index = this.entryIndexFind(link);
+        if (index < 0 || index >= this.definitions.length) { return; }
+
         this.noteAdd(this.definitions[index], link.dataset.mode);
     }
 
@@ -216,13 +237,16 @@ class Display {
     }
 
     onHistoryWheel(e) {
+        if (e.altKey) { return; }
         const delta = -e.deltaX || e.deltaY;
         if (delta > 0) {
             this.sourceTermView();
             e.preventDefault();
+            e.stopPropagation();
         } else if (delta < 0) {
             this.nextTermView();
             e.preventDefault();
+            e.stopPropagation();
         }
     }
 
@@ -230,15 +254,6 @@ class Display {
         throw new Error('Override me');
     }
 
-    isInitialized() {
-        return this.options !== null;
-    }
-
-    async initialize(options=null) {
-        await this.updateOptions(options);
-        yomichan.on('optionsUpdate', () => this.updateOptions(null));
-    }
-
     async updateOptions(options) {
         this.options = options ? options : await apiOptionsGet(this.getOptionsContext());
         this.updateDocumentOptions(this.options);
@@ -252,6 +267,7 @@ class Display {
         data.ankiEnabled = `${options.anki.enable}`;
         data.audioEnabled = `${options.audio.enable}`;
         data.compactGlossaries = `${options.general.compactGlossaries}`;
+        data.enableSearchTags = `${options.scanning.enableSearchTags}`;
         data.debug = `${options.general.debugInfo}`;
     }
 
@@ -285,13 +301,24 @@ class Display {
         this.interactive = interactive;
 
         if (interactive) {
-            Display.addEventListener(this.persistentEventListeners, document, 'keydown', this.onKeyDown.bind(this), false);
-            Display.addEventListener(this.persistentEventListeners, document, 'wheel', this.onWheel.bind(this), {passive: false});
-            Display.addEventListener(this.persistentEventListeners, document.querySelector('.action-previous'), 'click', this.onSourceTermView.bind(this));
-            Display.addEventListener(this.persistentEventListeners, document.querySelector('.action-next'), 'click', this.onNextTermView.bind(this));
-            Display.addEventListener(this.persistentEventListeners, document.querySelector('.navigation-header'), 'wheel', this.onHistoryWheel.bind(this), {passive: false});
+            const actionPrevious = document.querySelector('.action-previous');
+            const actionNext = document.querySelector('.action-next');
+            // const navigationHeader = document.querySelector('.navigation-header');
+
+            this.persistentEventListeners.addEventListener(document, 'keydown', this.onKeyDown.bind(this), false);
+            this.persistentEventListeners.addEventListener(document, 'wheel', this.onWheel.bind(this), {passive: false});
+            if (actionPrevious !== null) {
+                this.persistentEventListeners.addEventListener(actionPrevious, 'click', this.onSourceTermView.bind(this));
+            }
+            if (actionNext !== null) {
+                this.persistentEventListeners.addEventListener(actionNext, 'click', this.onNextTermView.bind(this));
+            }
+            // temporarily disabled
+            // if (navigationHeader !== null) {
+            //     this.persistentEventListeners.addEventListener(navigationHeader, 'wheel', this.onHistoryWheel.bind(this), {passive: false});
+            // }
         } else {
-            Display.clearEventListeners(this.persistentEventListeners);
+            this.persistentEventListeners.removeAllEventListeners();
         }
         this.setEventListenersActive(this.eventListenersActive);
     }
@@ -302,23 +329,23 @@ class Display {
         this.eventListenersActive = active;
 
         if (active) {
-            this.addEventListeners('.action-add-note', 'click', this.onNoteAdd.bind(this));
-            this.addEventListeners('.action-view-note', 'click', this.onNoteView.bind(this));
-            this.addEventListeners('.action-play-audio', 'click', this.onAudioPlay.bind(this));
-            this.addEventListeners('.kanji-link', 'click', this.onKanjiLookup.bind(this));
+            this.addMultipleEventListeners('.action-add-note', 'click', this.onNoteAdd.bind(this));
+            this.addMultipleEventListeners('.action-view-note', 'click', this.onNoteView.bind(this));
+            this.addMultipleEventListeners('.action-play-audio', 'click', this.onAudioPlay.bind(this));
+            this.addMultipleEventListeners('.kanji-link', 'click', this.onKanjiLookup.bind(this));
             if (this.options.scanning.enablePopupSearch) {
-                this.addEventListeners('.glossary-item', 'mouseup', this.onGlossaryMouseUp.bind(this));
-                this.addEventListeners('.glossary-item', 'mousedown', this.onGlossaryMouseDown.bind(this));
-                this.addEventListeners('.glossary-item', 'mousemove', this.onGlossaryMouseMove.bind(this));
+                this.addMultipleEventListeners('.term-glossary-item, .tag', 'mouseup', this.onGlossaryMouseUp.bind(this));
+                this.addMultipleEventListeners('.term-glossary-item, .tag', 'mousedown', this.onGlossaryMouseDown.bind(this));
+                this.addMultipleEventListeners('.term-glossary-item, .tag', 'mousemove', this.onGlossaryMouseMove.bind(this));
             }
         } else {
-            Display.clearEventListeners(this.eventListeners);
+            this.eventListeners.removeAllEventListeners();
         }
     }
 
-    addEventListeners(selector, type, listener, options) {
+    addMultipleEventListeners(selector, type, listener, options) {
         for (const node of this.container.querySelectorAll(selector)) {
-            Display.addEventListener(this.eventListeners, node, type, listener, options);
+            this.eventListeners.addEventListener(node, type, listener, options);
         }
     }
 
@@ -348,7 +375,6 @@ class Display {
 
     async setContentTerms(definitions, context, token) {
         if (!context) { throw new Error('Context expected'); }
-        if (!this.isInitialized()) { return; }
 
         this.setEventListenersActive(false);
 
@@ -356,11 +382,6 @@ class Display {
             window.focus();
         }
 
-        if (!this.displayGenerator.isInitialized()) {
-            await this.displayGenerator.initialize();
-            if (this.setContentToken !== token) { return; }
-        }
-
         this.definitions = definitions;
         if (context.disableHistory) {
             delete context.disableHistory;
@@ -404,7 +425,7 @@ class Display {
 
         this.setEventListenersActive(true);
 
-        const states = await apiDefinitionsAddable(definitions, ['term-kanji', 'term-kana'], this.getOptionsContext());
+        const states = await this.getDefinitionsAddable(definitions, ['term-kanji', 'term-kana']);
         if (this.setContentToken !== token) { return; }
 
         this.updateAdderButtons(states);
@@ -412,7 +433,6 @@ class Display {
 
     async setContentKanji(definitions, context, token) {
         if (!context) { throw new Error('Context expected'); }
-        if (!this.isInitialized()) { return; }
 
         this.setEventListenersActive(false);
 
@@ -420,11 +440,6 @@ class Display {
             window.focus();
         }
 
-        if (!this.displayGenerator.isInitialized()) {
-            await this.displayGenerator.initialize();
-            if (this.setContentToken !== token) { return; }
-        }
-
         this.definitions = definitions;
         if (context.disableHistory) {
             delete context.disableHistory;
@@ -446,7 +461,7 @@ class Display {
 
         for (let i = 0, ii = definitions.length; i < ii; ++i) {
             if (i > 0) {
-                await promiseTimeout(0);
+                await promiseTimeout(1);
                 if (this.setContentToken !== token) { return; }
             }
 
@@ -459,7 +474,7 @@ class Display {
 
         this.setEventListenersActive(true);
 
-        const states = await apiDefinitionsAddable(definitions, ['kanji'], this.getOptionsContext());
+        const states = await this.getDefinitionsAddable(definitions, ['kanji']);
         if (this.setContentToken !== token) { return; }
 
         this.updateAdderButtons(states);
@@ -498,6 +513,8 @@ class Display {
     }
 
     autoPlayAudio() {
+        if (this.definitions.length === 0) { return; }
+
         this.audioPlay(this.definitions[0], this.firstExpressionIndex, 0);
     }
 
@@ -597,9 +614,12 @@ class Display {
     }
 
     noteTryAdd(mode) {
-        const button = this.adderButtonFind(this.index, mode);
+        const index = this.index;
+        if (index < 0 || index >= this.definitions.length) { return; }
+
+        const button = this.adderButtonFind(index, mode);
         if (button !== null && !button.classList.contains('disabled')) {
-            this.noteAdd(this.definitions[this.index], mode);
+            this.noteAdd(this.definitions[index], mode);
         }
     }
 
@@ -698,7 +718,7 @@ class Display {
     async getScreenshot() {
         try {
             await this.setPopupVisibleOverride(false);
-            await Display.delay(1); // Wait for popup to be hidden.
+            await promiseTimeout(1); // Wait for popup to be hidden.
 
             const {format, quality} = this.options.anki.screenshot;
             const dataUrl = await apiScreenshotGet({format, quality});
@@ -767,8 +787,12 @@ class Display {
         return entry !== null ? entry.querySelector('.action-play-audio>img') : null;
     }
 
-    static delay(time) {
-        return new Promise((resolve) => setTimeout(resolve, time));
+    async getDefinitionsAddable(definitions, modes) {
+        try {
+            return await apiDefinitionsAddable(definitions, modes, this.getOptionsContext());
+        } catch (e) {
+            return [];
+        }
     }
 
     static indexOf(nodeList, node) {
@@ -780,19 +804,6 @@ class Display {
         return -1;
     }
 
-    static addEventListener(eventListeners, object, type, listener, options) {
-        if (object === null) { return; }
-        object.addEventListener(type, listener, options);
-        eventListeners.push([object, type, listener, options]);
-    }
-
-    static clearEventListeners(eventListeners) {
-        for (const [object, type, listener, options] of eventListeners) {
-            object.removeEventListener(type, listener, options);
-        }
-        eventListeners.length = 0;
-    }
-
     static getElementTop(element) {
         const elementRect = element.getBoundingClientRect();
         const documentRect = document.documentElement.getBoundingClientRect();
@@ -901,9 +912,12 @@ Display._onKeyDownHandlers = new Map([
 
     ['P', (self, e) => {
         if (e.altKey) {
-            const entry = self.getEntry(self.index);
+            const index = self.index;
+            if (index < 0 || index >= self.definitions.length) { return; }
+
+            const entry = self.getEntry(index);
             if (entry !== null && entry.dataset.type === 'term') {
-                self.audioPlay(self.definitions[self.index], self.firstExpressionIndex, self.index);
+                self.audioPlay(self.definitions[index], self.firstExpressionIndex, index);
             }
             return true;
         }
diff --git a/ext/mixed/js/template-handler.js b/ext/mixed/js/template-handler.js
new file mode 100644
index 00000000..a5a62937
--- /dev/null
+++ b/ext/mixed/js/template-handler.js
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+class TemplateHandler {
+    constructor(html) {
+        this._templates = new Map();
+
+        const doc = new DOMParser().parseFromString(html, 'text/html');
+        for (const template of doc.querySelectorAll('template')) {
+            this._setTemplate(template);
+        }
+    }
+
+    _setTemplate(template) {
+        const idMatch = template.id.match(/^([a-z-]+)-template$/);
+        if (!idMatch) {
+            throw new Error(`Invalid template ID: ${template.id}`);
+        }
+        this._templates.set(idMatch[1], template);
+    }
+
+    instantiate(name) {
+        const template = this._templates.get(name);
+        return document.importNode(template.content.firstChild, true);
+    }
+
+    instantiateFragment(name) {
+        const template = this._templates.get(name);
+        return document.importNode(template.content, true);
+    }
+}
diff --git a/ext/mixed/js/text-scanner.js b/ext/mixed/js/text-scanner.js
index 88f1e27a..ff0eac8b 100644
--- a/ext/mixed/js/text-scanner.js
+++ b/ext/mixed/js/text-scanner.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global docRangeFromPoint, TextSourceRange, DOM*/
 
 class TextScanner {
     constructor(node, ignoreNodes, ignoreElements, ignorePoints) {
@@ -30,7 +31,7 @@ class TextScanner {
         this.options = null;
 
         this.enabled = false;
-        this.eventListeners = [];
+        this.eventListeners = new EventListenerCollection();
 
         this.primaryTouchIdentifier = null;
         this.preventNextContextMenu = false;
@@ -140,24 +141,24 @@ class TextScanner {
         const textSourceCurrentPrevious = this.textSourceCurrent !== null ? this.textSourceCurrent.clone() : null;
 
         this.searchAt(primaryTouch.clientX, primaryTouch.clientY, 'touchStart')
-        .then(() => {
-            if (
-                this.textSourceCurrent === null ||
-                this.textSourceCurrent.equals(textSourceCurrentPrevious)
-            ) {
-                return;
-            }
+            .then(() => {
+                if (
+                    this.textSourceCurrent === null ||
+                    this.textSourceCurrent.equals(textSourceCurrentPrevious)
+                ) {
+                    return;
+                }
 
-            this.preventScroll = true;
-            this.preventNextContextMenu = true;
-            this.preventNextMouseDown = true;
-        });
+                this.preventScroll = true;
+                this.preventNextContextMenu = true;
+                this.preventNextMouseDown = true;
+            });
     }
 
     onTouchEnd(e) {
         if (
             this.primaryTouchIdentifier === null ||
-            TextScanner.getIndexOfTouch(e.changedTouches, this.primaryTouchIdentifier) < 0
+            TextScanner.getTouch(e.changedTouches, this.primaryTouchIdentifier) === null
         ) {
             return;
         }
@@ -180,13 +181,11 @@ class TextScanner {
             return;
         }
 
-        const touches = e.changedTouches;
-        const index = TextScanner.getIndexOfTouch(touches, this.primaryTouchIdentifier);
-        if (index < 0) {
+        const primaryTouch = TextScanner.getTouch(e.changedTouches, this.primaryTouchIdentifier);
+        if (primaryTouch === null) {
             return;
         }
 
-        const primaryTouch = touches[index];
         this.searchAt(primaryTouch.clientX, primaryTouch.clientY, 'touchMove');
 
         e.preventDefault(); // Disable scroll
@@ -228,7 +227,7 @@ class TextScanner {
             }
         } else {
             if (this.enabled) {
-                this.clearEventListeners();
+                this.eventListeners.removeAllEventListeners();
                 this.enabled = false;
             }
             this.onSearchClear(false);
@@ -236,13 +235,13 @@ class TextScanner {
     }
 
     hookEvents() {
-        let eventListeners = this.getMouseEventListeners();
+        let eventListenerInfos = this.getMouseEventListeners();
         if (this.options.scanning.touchInputEnabled) {
-            eventListeners = eventListeners.concat(this.getTouchEventListeners());
+            eventListenerInfos = eventListenerInfos.concat(this.getTouchEventListeners());
         }
 
-        for (const [node, type, listener, options] of eventListeners) {
-            this.addEventListener(node, type, listener, options);
+        for (const [node, type, listener, options] of eventListenerInfos) {
+            this.eventListeners.addEventListener(node, type, listener, options);
         }
     }
 
@@ -267,18 +266,6 @@ class TextScanner {
         ];
     }
 
-    addEventListener(node, type, listener, options) {
-        node.addEventListener(type, listener, options);
-        this.eventListeners.push([node, type, listener, options]);
-    }
-
-    clearEventListeners() {
-        for (const [node, type, listener, options] of this.eventListeners) {
-            node.removeEventListener(type, listener, options);
-        }
-        this.eventListeners = [];
-    }
-
     setOptions(options) {
         this.options = options;
         this.setEnabled(this.options.general.enable);
@@ -367,13 +354,12 @@ class TextScanner {
         }
     }
 
-    static getIndexOfTouch(touchList, identifier) {
-        for (const i in touchList) {
-            const t = touchList[i];
-            if (t.identifier === identifier) {
-                return i;
+    static getTouch(touchList, identifier) {
+        for (const touch of touchList) {
+            if (touch.identifier === identifier) {
+                return touch;
             }
         }
-        return -1;
+        return null;
     }
 }