Definition collapsing when overflowing (#1575)

* Add double-down-chevron.svg

* Add options

* Update dictionary importers

* Update settings

* Add support for collapsible definitions

* Improve case when there is a very small amount of overflow

* Fix incorrect enabled state of newly imported dictionaries

19 files changed, 520 insertions, 30 deletions

diff --git a/ext/css/display.css b/ext/css/display.css
index 887a04a6..c8669fa2 100644
--- a/ext/css/display.css
+++ b/ext/css/display.css
@@ -101,6 +101,9 @@
     --animation-duration: 0.125s;
     --animation-duration2: calc(2 * var(--animation-duration));
 
+    --collapsible-definition-line-count: 3;
+    --collapsible-definition-test-offset: 0.2em;
+
     /* Colors */
     --background-color: #ffffff;
     --glossary-image-background-color: #eeeeee;
@@ -1154,6 +1157,74 @@ button.action-button[data-icon=source-term]::before {
     opacity: 0;
     white-space: pre-wrap;
 }
+.definition-item {
+    display: list-item;
+    position: relative;
+}
+.definition-item-inner.collapsible.collapsed {
+    max-height: calc(1em * var(--collapsible-definition-line-count) * var(--line-height));
+    overflow: hidden;
+}
+.definition-item-inner.collapse-test {
+    max-height: calc(1em * var(--collapsible-definition-line-count) * var(--line-height) + var(--collapsible-definition-test-offset));
+    overflow: hidden;
+}
+.definition-item-inner {
+    display: flex;
+    flex-flow: row nowrap;
+}
+.definition-item-content {
+    flex: 1 1 auto;
+    background-color: transparent;
+    transition: background-color var(--animation-duration) ease-in-out;
+}
+button.definition-item-expansion-button {
+    --button-content-color: var(--text-color-light4);
+    --button-border-color: transparent;
+    --button-background-color: transparent;
+
+    --button-hover-content-color: var(--text-color-light1);
+    --button-hover-border-color: var(--accent-color-lighter);
+    --button-hover-background-color: var(--accent-color-lighter);
+
+    --button-active-content-color: var(--text-color);
+    --button-active-border-color: var(--accent-color-light);
+    --button-active-background-color: var(--accent-color-light);
+
+    --button-padding-vertical: 0;
+    --button-padding-horizontal: 0.125em;
+
+    flex: 0 0 auto;
+    order: 1;
+    border-radius: 0;
+    border: 0;
+}
+.definition-item-inner:not(.collapsible)>button.definition-item-expansion-button {
+    display: none;
+}
+button.definition-item-expansion-button:hover+.definition-item-content,
+button.definition-item-expansion-button:active+.definition-item-content,
+button.definition-item-expansion-button:focus+.definition-item-content {
+    background-color: var(--accent-color-transparent25);
+}
+button.definition-item-expansion-button:focus:not(:focus-visible)+.definition-item-content {
+    background-color: transparent;
+}
+button.definition-item-expansion-button:focus:hover+.definition-item-content,
+button.definition-item-expansion-button:focus:active+.definition-item-content,
+button.definition-item-expansion-button:focus:focus-visible+.definition-item-content {
+    background-color: var(--accent-color-transparent25);
+}
+.definition-item-expansion-button-icon {
+    transform: rotate(0deg);
+    width: calc(16em / var(--font-size-no-units));
+    height: calc(16em / var(--font-size-no-units));
+    background-color: var(--button-current-content-color);
+    transition: background-color var(--animation-duration) ease-in-out;
+}
+.definition-item-inner.collapsible:not(.collapsed)>button.definition-item-expansion-button>.definition-item-expansion-button-icon {
+    transform: rotate(180deg);
+}
 
 
 /* Frequencies */
diff --git a/ext/css/material.css b/ext/css/material.css
index 703f1268..08345769 100644
--- a/ext/css/material.css
+++ b/ext/css/material.css
@@ -234,6 +234,7 @@
 .icon[data-icon=question-mark-thick]     { --icon-image: url(/images/question-mark-thick.svg); }
 .icon[data-icon=left-chevron]            { --icon-image: url(/images/left-chevron.svg); }
 .icon[data-icon=right-chevron]           { --icon-image: url(/images/right-chevron.svg); }
+.icon[data-icon=double-down-chevron]     { --icon-image: url(/images/double-down-chevron.svg); }
 .icon[data-icon=plus-thick]              { --icon-image: url(/images/plus-thick.svg); }
 .icon[data-icon=clipboard]               { --icon-image: url(/images/clipboard.svg); }
 .icon[data-icon=key]                     { --icon-image: url(/images/key.svg); }
diff --git a/ext/css/settings.css b/ext/css/settings.css
index e2485925..22439409 100644
--- a/ext/css/settings.css
+++ b/ext/css/settings.css
@@ -47,6 +47,7 @@
     --outline-item-icon-size: 32px;
     --input-short-width: calc(var(--input-width-large) / 2 - var(--padding) / 2);
     --input-short-height: 24px;
+    --input-medium-width: calc(var(--input-width-large) * 0.75);
     --fab-button-size: 56px;
     --fab-button-padding: 16px;
     --modal-width: 600px;
@@ -657,6 +658,11 @@ input[type=number].short-width,
 select.short-width {
     width: var(--input-short-width);
 }
+input[type=text].medium-width,
+input[type=number].medium-width,
+select.medium-width {
+    width: var(--input-medium-width);
+}
 input[type=text].short-height,
 input[type=number].short-height,
 select.short-height {
@@ -2125,6 +2131,39 @@ button.hotkey-list-item-enabled-button[data-scope-count='0'] {
     background-color: var(--warning-color);
 }
 
+.collapsible-dictionary-list {
+    width: 100%;
+    display: flex;
+    flex-flow: column nowrap;
+    align-items: stretch;
+}
+.collapsible-dictionary-item {
+    display: flex;
+    flex-flow: row nowrap;
+    align-items: center;
+    margin-left: calc(var(--modal-padding-horizontal) * -1);
+    margin-right: calc(var(--modal-padding-horizontal) * -1);
+    padding: var(--settings-group-inner-horizontal-padding-fourth) var(--modal-padding-horizontal);
+}
+.collapsible-dictionary-item:not(:first-child) {
+    border-top: var(--thin-border-size) solid var(--separator-color2);
+}
+.collapsible-dictionary-cell {
+    display: flex;
+    flex-flow: row nowrap;
+    align-items: center;
+}
+.collapsible-dictionary-cell:first-of-type {
+    flex: 1 1 auto;
+}
+.collapsible-dictionary-cell:not(:first-of-type) {
+    flex: 0 0 auto;
+    margin-left: 1em;
+}
+.collapsible-dictionary-cell-label {
+    margin-left: 0.375em;
+}
+
 
 /* Generic layouts */
 .margin-above {
diff --git a/ext/data/schemas/options-schema.json b/ext/data/schemas/options-schema.json
index 89e2d361..d829b392 100644
--- a/ext/data/schemas/options-schema.json
+++ b/ext/data/schemas/options-schema.json
@@ -732,7 +732,8 @@
                                     "required": [
                                         "priority",
                                         "enabled",
-                                        "allowSecondarySearches"
+                                        "allowSecondarySearches",
+                                        "definitionsCollapsible"
                                     ],
                                     "properties": {
                                         "priority": {
@@ -746,6 +747,11 @@
                                         "allowSecondarySearches": {
                                             "type": "boolean",
                                             "default": false
+                                        },
+                                        "definitionsCollapsible": {
+                                            "type": "string",
+                                            "enum": ["not-collapsible", "expanded", "collapsed"],
+                                            "default": "not-collapsible"
                                         }
                                     }
                                 }
diff --git a/ext/display-templates.html b/ext/display-templates.html
index 20978d65..25beacb0 100644
--- a/ext/display-templates.html
+++ b/ext/display-templates.html
@@ -45,7 +45,16 @@
         <div class="expression-tag-list tag-list"></div>
     </div>
 </div></template>
-<template id="definition-item-template"><li class="definition-item"><div class="definition-tag-list tag-list"></div><div class="definition-disambiguation-list"></div><ul class="glossary-list"></ul></li></template>
+<template id="definition-item-template" data-remove-whitespace-text="true"><li class="definition-item">
+    <div class="definition-item-inner">
+        <button class="definition-item-expansion-button"><div class="definition-item-expansion-button-icon icon" data-icon="double-down-chevron"></div></button>
+        <div class="definition-item-content">
+            <div class="definition-tag-list tag-list"></div>
+            <div class="definition-disambiguation-list"></div>
+            <ul class="glossary-list"></ul>
+        </div>
+    </div>
+</li></template>
 <template id="definition-disambiguation-template"><span class="definition-disambiguation"></span></template>
 <template id="glossary-item-template"><li class="glossary-item click-scannable"><span class="glossary-separator"> </span><span class="glossary"></span></li></template>
 <template id="glossary-item-image-template"><li class="glossary-item click-scannable" data-has-image="true"><span class="glossary-separator"> </span><span class="glossary"><a class="glossary-image-link" target="_blank" rel="noreferrer noopener"><span class="glossary-image-container"><span class="glossary-image-aspect-ratio-sizer"></span><img class="glossary-image" alt=""><span class="glossary-image-container-overlay"></span></span><span class="glossary-image-link-text">Image</span></a> <span class="glossary-image-description"></span></span></li></template>
diff --git a/ext/images/double-down-chevron.svg b/ext/images/double-down-chevron.svg
new file mode 100644
index 00000000..90684054
--- /dev/null
+++ b/ext/images/double-down-chevron.svg
@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8"?><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16"><path d="M3 .5l-2 2 7 7 7-7-2-2-5 5-5-5zm0 6l-2 2 7 7 7-7-2-2-5 5-5-5z"/></svg>
\ No newline at end of file
diff --git a/ext/js/data/options-util.js b/ext/js/data/options-util.js
index 5b2e2bd3..ca122e89 100644
--- a/ext/js/data/options-util.js
+++ b/ext/js/data/options-util.js
@@ -755,9 +755,13 @@ class OptionsUtil {
         //  Removed global option useSettingsV2.
         //  Added part-of-speech field template.
         //  Added an argument to hotkey inputs.
+        //  Added definitionsCollapsible to dictionary options.
         await this._applyAnkiFieldTemplatesPatch(options, '/data/templates/anki-field-templates-upgrade-v10.handlebars');
         delete options.global.useSettingsV2;
         for (const profile of options.profiles) {
+            for (const dictionaryOptions of Object.values(profile.options.dictionaries)) {
+                dictionaryOptions.definitionsCollapsible = 'not-collapsible';
+            }
             for (const hotkey of profile.options.inputs.hotkeys) {
                 switch (hotkey.action) {
                     case 'previousEntry':
diff --git a/ext/js/display/display.js b/ext/js/display/display.js
index ee2448d6..b17a6168 100644
--- a/ext/js/display/display.js
+++ b/ext/js/display/display.js
@@ -23,6 +23,7 @@
  * DisplayHistory
  * DisplayNotification
  * DocumentUtil
+ * ElementOverflowController
  * FrameEndpoint
  * Frontend
  * HotkeyHelpController
@@ -114,6 +115,7 @@ class Display extends EventDispatcher {
         this._ankiNoteNotificationEventListeners = null;
         this._queryPostProcessor = null;
         this._optionToggleHotkeyHandler = new OptionToggleHotkeyHandler(this);
+        this._elementOverflowController = new ElementOverflowController();
 
         this._hotkeyHandler.registerActions([
             ['close',             () => { this._onHotkeyClose(); }],
@@ -305,6 +307,7 @@ class Display extends EventDispatcher {
         this._hotkeyHelpController.setOptions(options);
         this._displayGenerator.updateHotkeys();
         this._hotkeyHelpController.setupNode(document.documentElement);
+        this._elementOverflowController.setOptions(options);
 
         this._queryParser.setOptions({
             selectedParser: options.parsing.selectedParser,
@@ -535,6 +538,7 @@ class Display extends EventDispatcher {
             this._hideAnkiNoteErrors(false);
             this._definitions = [];
             this._definitionNodes = [];
+            this._elementOverflowController.clearElements();
 
             // Prepare
             const urlSearchParams = new URLSearchParams(location.search);
@@ -966,6 +970,8 @@ class Display extends EventDispatcher {
             if (focusEntry === i) {
                 this._focusEntry(i, false);
             }
+
+            this._elementOverflowController.addElements(entry);
         }
 
         if (typeof scrollX === 'number' || typeof scrollY === 'number') {
diff --git a/ext/js/display/element-overflow-controller.js b/ext/js/display/element-overflow-controller.js
new file mode 100644
index 00000000..ccea1417
--- /dev/null
+++ b/ext/js/display/element-overflow-controller.js
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * 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/>.
+ */
+
+class ElementOverflowController {
+    constructor() {
+        this._elements = [];
+        this._checkTimer = null;
+        this._eventListeners = new EventListenerCollection();
+        this._windowEventListeners = new EventListenerCollection();
+        this._dictionaries = new Map();
+        this._updateBind = this._update.bind(this);
+        this._onWindowResizeBind = this._onWindowResize.bind(this);
+        this._onToggleButtonClickBind = this._onToggleButtonClick.bind(this);
+    }
+
+    setOptions(options) {
+        this._dictionaries.clear();
+        for (const [dictionary, {definitionsCollapsible}] of Object.entries(options.dictionaries)) {
+            let collapsible = false;
+            let collapsed = false;
+            switch (definitionsCollapsible) {
+                case 'expanded':
+                    collapsible = true;
+                    break;
+                case 'collapsed':
+                    collapsible = true;
+                    collapsed = true;
+                    break;
+            }
+            if (!collapsible) { continue; }
+            this._dictionaries.set(dictionary, {collapsed});
+        }
+    }
+
+    addElements(entry) {
+        if (this._dictionaries.size === 0) { return; }
+
+        const elements = entry.querySelectorAll('.definition-item-inner');
+        let any = false;
+        for (const element of elements) {
+            const {dictionary} = element.parentNode.dataset;
+            const dictionaryInfo = this._dictionaries.get(dictionary);
+            if (typeof dictionaryInfo === 'undefined') { continue; }
+
+            this._updateElement(element);
+            this._elements.push(element);
+
+            if (dictionaryInfo.collapsed) {
+                element.classList.add('collapsed');
+            }
+
+            const button = element.querySelector('.definition-item-expansion-button');
+            if (button !== null) {
+                this._eventListeners.addEventListener(button, 'click', this._onToggleButtonClickBind, false);
+            }
+
+            any = true;
+        }
+
+        if (any && this._windowEventListeners.size === 0) {
+            this._windowEventListeners.addEventListener(window, 'resize', this._onWindowResizeBind, false);
+        }
+    }
+
+    clearElements() {
+        if (this._elements.length === 0) { return; }
+        this._elements = [];
+        this._windowEventListeners.removeAllEventListeners();
+    }
+
+    // Private
+
+    _onWindowResize() {
+        if (this._checkTimer !== null) {
+            this._cancelIdleCallback(this._checkTimer);
+        }
+        this._checkTimer = this._requestIdleCallback(this._updateBind, 100);
+    }
+
+    _onToggleButtonClick(e) {
+        const container = e.currentTarget.closest('.definition-item-inner');
+        if (container === null) { return; }
+        container.classList.toggle('collapsed');
+    }
+
+    _update() {
+        for (const element of this._elements) {
+            this._updateElement(element);
+        }
+    }
+
+    _updateElement(element) {
+        const {classList} = element;
+        classList.add('collapse-test');
+        const collapsible = element.scrollHeight > element.clientHeight || element.scrollWidth > element.clientWidth;
+        classList.toggle('collapsible', collapsible);
+        classList.remove('collapse-test');
+    }
+
+    _requestIdleCallback(callback, timeout) {
+        if (typeof requestIdleCallback === 'function') {
+            return requestIdleCallback(callback, {timeout});
+        } else {
+            return setTimeout(callback, timeout);
+        }
+    }
+
+    _cancelIdleCallback(handle) {
+        if (typeof cancelIdleCallback === 'function') {
+            cancelIdleCallback(handle);
+        } else {
+            clearTimeout(handle);
+        }
+    }
+}
diff --git a/ext/js/pages/settings/backup-controller.js b/ext/js/pages/settings/backup-controller.js
index 6f6614b6..933f0e2a 100644
--- a/ext/js/pages/settings/backup-controller.js
+++ b/ext/js/pages/settings/backup-controller.js
@@ -404,7 +404,7 @@ class BackupController {
         const dictionaries = await this._settingsController.getDictionaryInfo();
         for (const {options: {dictionaries: optionsDictionaries}} of optionsFull.profiles) {
             for (const {title} of dictionaries) {
-                optionsDictionaries[title] = DictionaryController.createDefaultDictionarySettings();
+                optionsDictionaries[title] = DictionaryController.createDefaultDictionarySettings(false);
             }
         }
 
diff --git a/ext/js/pages/settings/collapsible-dictionary-controller.js b/ext/js/pages/settings/collapsible-dictionary-controller.js
new file mode 100644
index 00000000..a3a1df62
--- /dev/null
+++ b/ext/js/pages/settings/collapsible-dictionary-controller.js
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * 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
+ * ObjectPropertyAccessor
+ */
+
+class CollapsibleDictionaryController {
+    constructor(settingsController) {
+        this._settingsController = settingsController;
+        this._getDictionaryInfoToken = null;
+        this._dictionaryInfoMap = new Map();
+        this._container = null;
+        this._selects = [];
+        this._allSelect = null;
+        this._eventListeners = new EventListenerCollection();
+    }
+
+    async prepare() {
+        this._container = document.querySelector('#collapsible-dictionary-list');
+
+        await this._onDatabaseUpdated();
+        await this._updateOptions();
+
+        yomichan.on('databaseUpdated', this._onDatabaseUpdated.bind(this));
+        this._settingsController.on('optionsChanged', this._onOptionsChanged.bind(this));
+    }
+
+    // Private
+
+    async _onDatabaseUpdated() {
+        const token = {};
+        this._getDictionaryInfoToken = token;
+        const dictionaries = await this._settingsController.getDictionaryInfo();
+        if (this._getDictionaryInfoToken !== token) { return; }
+        this._getDictionaryInfoToken = null;
+
+        this._dictionaryInfoMap.clear();
+        for (const entry of dictionaries) {
+            this._dictionaryInfoMap.set(entry.title, entry);
+        }
+
+        await this._updateOptions();
+    }
+
+    _onOptionsChanged({options}) {
+        this._eventListeners.removeAllEventListeners();
+        this._selects = [];
+
+        const {dictionaries} = options;
+
+        const fragment = document.createDocumentFragment();
+
+        this._setupAllSelect(fragment, options);
+
+        for (const dictionary of Object.keys(dictionaries)) {
+            const dictionaryInfo = this._dictionaryInfoMap.get(dictionary);
+            if (typeof dictionaryInfo === 'undefined') { continue; }
+
+            const select = this._addSelect(fragment, dictionary, `rev.${dictionaryInfo.revision}`);
+            select.dataset.setting = ObjectPropertyAccessor.getPathString(['dictionaries', dictionary, 'definitionsCollapsible']);
+            this._eventListeners.addEventListener(select, 'settingChanged', this._onDefinitionsCollapsibleChange.bind(this), false);
+
+            this._selects.push(select);
+        }
+
+        this._container.textContent = '';
+        this._container.appendChild(fragment);
+    }
+
+    _onDefinitionsCollapsibleChange() {
+        this._updateAllSelectFresh();
+    }
+
+    _onAllSelectChange(e) {
+        const {value} = e.currentTarget;
+        if (value === 'varies') { return; }
+        this._setDefinitionsCollapsibleAll(value);
+    }
+
+    _setupAllSelect(fragment, options) {
+        const select = this._addSelect(fragment, 'All', '');
+
+        const option = document.createElement('option');
+        option.value = 'varies';
+        option.textContent = 'Varies';
+        option.disabled = true;
+        select.appendChild(option);
+
+        this._eventListeners.addEventListener(select, 'change', this._onAllSelectChange.bind(this), false);
+
+        this._allSelect = select;
+        this._updateAllSelect(options);
+    }
+
+    _addSelect(fragment, dictionary, version) {
+        const node = this._settingsController.instantiateTemplate('collapsible-dictionary-item');
+        fragment.appendChild(node);
+
+        const nameNode = node.querySelector('.dictionary-title');
+        nameNode.textContent = dictionary;
+
+        const versionNode = node.querySelector('.dictionary-version');
+        versionNode.textContent = version;
+
+        return node.querySelector('.definitions-collapsible');
+    }
+
+    async _updateOptions() {
+        const options = await this._settingsController.getOptions();
+        this._onOptionsChanged({options});
+    }
+
+    async _updateAllSelectFresh() {
+        this._updateAllSelect(await this._settingsController.getOptions());
+    }
+
+    _updateAllSelect(options) {
+        let value = null;
+        let varies = false;
+        for (const {definitionsCollapsible} of Object.values(options.dictionaries)) {
+            if (value === null) {
+                value = definitionsCollapsible;
+            } else if (value !== definitionsCollapsible) {
+                varies = true;
+                break;
+            }
+        }
+
+        this._allSelect.value = (varies || value === null ? 'varies' : value);
+    }
+
+    async _setDefinitionsCollapsibleAll(value) {
+        const options = await this._settingsController.getOptions();
+        const targets = [];
+        for (const dictionary of Object.keys(options.dictionaries)) {
+            const path = ObjectPropertyAccessor.getPathString(['dictionaries', dictionary, 'definitionsCollapsible']);
+            targets.push({action: 'set', path, value});
+        }
+        await this._settingsController.modifyProfileSettings(targets);
+        for (const select of this._selects) {
+            select.value = value;
+        }
+    }
+}
\ No newline at end of file
diff --git a/ext/js/pages/settings/dictionary-controller.js b/ext/js/pages/settings/dictionary-controller.js
index 17abfa13..65edcb67 100644
--- a/ext/js/pages/settings/dictionary-controller.js
+++ b/ext/js/pages/settings/dictionary-controller.js
@@ -248,6 +248,15 @@ class DictionaryController {
         this._updateDictionariesEnabledWarnings(options);
     }
 
+    static createDefaultDictionarySettings(enabled) {
+        return {
+            priority: 0,
+            enabled,
+            allowSecondarySearches: false,
+            definitionsCollapsible: 'not-collapsible'
+        };
+    }
+
     // Private
 
     _onOptionsChanged({options}) {
@@ -535,7 +544,7 @@ class DictionaryController {
                 targets.push({
                     action: 'set',
                     path,
-                    value: DictionaryController.createDefaultDictionarySettings()
+                    value: DictionaryController.createDefaultDictionarySettings(false)
                 });
             }
         }
@@ -548,12 +557,4 @@ class DictionaryController {
     _triggerStorageChanged() {
         yomichan.trigger('storageChanged');
     }
-
-    static createDefaultDictionarySettings() {
-        return {
-            enabled: false,
-            allowSecondarySearches: false,
-            priority: 0
-        };
-    }
 }
diff --git a/ext/js/pages/settings/dictionary-import-controller.js b/ext/js/pages/settings/dictionary-import-controller.js
index ce724263..afa45899 100644
--- a/ext/js/pages/settings/dictionary-import-controller.js
+++ b/ext/js/pages/settings/dictionary-import-controller.js
@@ -16,6 +16,7 @@
  */
 
 /* global
+ * DictionaryController
  * DictionaryDatabase
  * DictionaryImporter
  * ObjectPropertyAccessor
@@ -212,7 +213,7 @@ class DictionaryImportController {
         const profileCount = optionsFull.profiles.length;
         for (let i = 0; i < profileCount; ++i) {
             const {options} = optionsFull.profiles[i];
-            const value = this._createDictionaryOptions();
+            const value = DictionaryController.createDefaultDictionarySettings(true);
             const path1 = ObjectPropertyAccessor.getPathString(['profiles', i, 'options', 'dictionaries', title]);
             targets.push({action: 'set', path: path1, value});
 
@@ -291,14 +292,6 @@ class DictionaryImportController {
         });
     }
 
-    _createDictionaryOptions() {
-        return {
-            priority: 0,
-            enabled: true,
-            allowSecondarySearches: false
-        };
-    }
-
     _errorToString(error) {
         error = (typeof error.toString === 'function' ? error.toString() : `${error}`);
 
diff --git a/ext/js/pages/settings/settings-main.js b/ext/js/pages/settings/settings-main.js
index 3618836c..2560685c 100644
--- a/ext/js/pages/settings/settings-main.js
+++ b/ext/js/pages/settings/settings-main.js
@@ -20,6 +20,7 @@
  * AnkiTemplatesController
  * AudioController
  * BackupController
+ * CollapsibleDictionaryController
  * DictionaryController
  * DictionaryImportController
  * DocumentFocusController
@@ -146,6 +147,9 @@ async function setupGenericSettingsController(genericSettingController) {
         const mecabController = new MecabController();
         mecabController.prepare();
 
+        const collapsibleDictionaryController = new CollapsibleDictionaryController(settingsController);
+        collapsibleDictionaryController.prepare();
+
         await Promise.all(preparePromises);
 
         document.documentElement.dataset.loaded = 'true';
diff --git a/ext/popup.html b/ext/popup.html
index 36cff420..76a0032b 100644
--- a/ext/popup.html
+++ b/ext/popup.html
@@ -105,6 +105,7 @@
 <script src="/js/display/display-notification.js"></script>
 <script src="/js/display/display-profile-selection.js"></script>
 <script src="/js/display/display-resizer.js"></script>
+<script src="/js/display/element-overflow-controller.js"></script>
 <script src="/js/display/option-toggle-hotkey-handler.js"></script>
 <script src="/js/display/query-parser.js"></script>
 <script src="/js/dom/document-focus-controller.js"></script>
diff --git a/ext/search.html b/ext/search.html
index 4ef8860f..d67dca45 100644
--- a/ext/search.html
+++ b/ext/search.html
@@ -89,6 +89,7 @@
 <script src="/js/display/display-generator.js"></script>
 <script src="/js/display/display-history.js"></script>
 <script src="/js/display/display-notification.js"></script>
+<script src="/js/display/element-overflow-controller.js"></script>
 <script src="/js/display/option-toggle-hotkey-handler.js"></script>
 <script src="/js/display/query-parser.js"></script>
 <script src="/js/display/search-display-controller.js"></script>
diff --git a/ext/settings.html b/ext/settings.html
index 3de183db..712dda3f 100644
--- a/ext/settings.html
+++ b/ext/settings.html
@@ -737,6 +737,14 @@
                 </p>
             </div>
         </div>
+        <div class="settings-item settings-item-button advanced-only" data-modal-action="show,collapsible-dictionaries"><div class="settings-item-inner">
+            <div class="settings-item-left">
+                <div class="settings-item-label">Configure collapsible dictionaries&hellip;</div>
+            </div>
+            <div class="settings-item-right open-panel-button-container">
+                <button class="icon-button"><span class="icon-button-inner"><span class="icon" data-icon="material-right-arrow"></span></span></button>
+            </div>
+        </div></div>
         <div class="settings-item settings-item-button" data-modal-action="show,custom-css"><div class="settings-item-inner">
             <div class="settings-item-left">
                 <div class="settings-item-label">Configure custom CSS&hellip;</div>
@@ -2095,6 +2103,24 @@
     </div>
 </div></div>
 
+<div id="collapsible-dictionaries-modal" class="modal" tabindex="-1" role="dialog" hidden><div class="modal-content">
+    <div class="modal-header">
+        <div class="modal-title">Collapsible Dictionaries</div>
+        <div class="modal-header-button-container">
+            <div class="modal-header-button-group">
+                <button class="icon-button modal-header-button" data-modal-action="expand"><span class="icon-button-inner"><span class="icon" data-icon="expand"></span></span></button>
+                <button class="icon-button modal-header-button" data-modal-action="collapse"><span class="icon-button-inner"><span class="icon" data-icon="collapse"></span></span></button>
+            </div>
+        </div>
+    </div>
+    <div class="modal-body">
+        <div id="collapsible-dictionary-list" class="collapsible-dictionary-list"></div>
+    </div>
+    <div class="modal-footer">
+        <button data-modal-action="hide">Close</button>
+    </div>
+</div></div>
+
 
 <!-- Dictionary templates -->
 <template id="dictionary-template"><div class="settings-item dictionary-item">
@@ -2187,6 +2213,19 @@
     </div>
 </div></div></template>
 
+<template id="collapsible-dictionary-item-template"><div class="collapsible-dictionary-item">
+    <div class="collapsible-dictionary-cell">
+        <span class="dictionary-info-label"><strong class="dictionary-title"></strong> <span class="light dictionary-version"></span></span>
+    </div>
+    <div class="collapsible-dictionary-cell">
+        <select class="definitions-collapsible medium-width">
+            <option value="not-collapsible">Not collapsible</option>
+            <option value="collapsed">Collapsed</option>
+            <option value="expanded">Expanded</option>
+        </select>
+    </div>
+</div></template>
+
 
 <!-- Custom CSS modal -->
 <div id="custom-css-modal" class="modal modal-left" tabindex="-1" role="dialog" hidden><div class="modal-content-container1">
@@ -3280,6 +3319,7 @@
 <script src="/js/pages/settings/anki-templates-controller.js"></script>
 <script src="/js/pages/settings/audio-controller.js"></script>
 <script src="/js/pages/settings/backup-controller.js"></script>
+<script src="/js/pages/settings/collapsible-dictionary-controller.js"></script>
 <script src="/js/pages/settings/dictionary-controller.js"></script>
 <script src="/js/pages/settings/dictionary-import-controller.js"></script>
 <script src="/js/pages/settings/extension-keyboard-shortcuts-controller.js"></script>
diff --git a/resources/icons.svg b/resources/icons.svg
index 9621d551..04690850 100644
--- a/resources/icons.svg
+++ b/resources/icons.svg
@@ -12,7 +12,7 @@
    inkscape:export-ydpi="192"
    inkscape:export-xdpi="192"
    sodipodi:docname="icons.svg"
-   inkscape:version="1.0.2 (e86c870879, 2021-01-15, custom)"
+   inkscape:version="0.92.4 (5da689c313, 2019-01-14)"
    id="svg8"
    version="1.1"
    viewBox="0 0 16 16"
@@ -26,17 +26,17 @@
      inkscape:pageopacity="0.0"
      inkscape:pageshadow="2"
      inkscape:zoom="22.627417"
-     inkscape:cx="8.8042238"
-     inkscape:cy="5.555245"
+     inkscape:cx="8.8116705"
+     inkscape:cy="3.394636"
      inkscape:document-units="px"
-     inkscape:current-layer="layer51"
+     inkscape:current-layer="g5298"
      showgrid="true"
      units="px"
      inkscape:snap-center="true"
      inkscape:window-width="1920"
      inkscape:window-height="1017"
      inkscape:window-x="-8"
-     inkscape:window-y="-8"
+     inkscape:window-y="-2"
      inkscape:window-maximized="1"
      viewbox-height="16"
      showguides="true"
@@ -1605,11 +1605,23 @@
   <g
      inkscape:groupmode="layer"
      id="layer51"
-     inkscape:label="Key">
+     inkscape:label="Key"
+     style="display:none">
     <path
        id="path1091"
        style="fill:#000000;stroke-linecap:round;stroke-linejoin:round"
        d="M 10.662109,1 C 8.349293,1.0478398 6.4995053,2.9366893 6.5,5.25 6.5002349,5.62267 6.5494854,5.9936904 6.6464844,6.3535156 L 0.75,12.25 V 13.5 L 2,15 H 4 L 4.5,14.5 V 13 H 6 V 11.5 H 7.5 V 10 H 9 L 9.6464844,9.3535156 C 10.00631,9.4505146 10.37733,9.4997651 10.75,9.5 13.09721,9.5 15,7.5972102 15,5.25 15,2.9027898 13.09721,1 10.75,1 10.7207,0.99969706 10.6914,0.99969706 10.66211,1 Z M 11.5,3 C 12.328427,3 13,3.6715729 13,4.5 13,5.3284271 12.328427,6 11.5,6 10.671573,6 10,5.3284271 10,4.5 10,3.6715729 10.671573,3 11.5,3 Z M 6.75,7.75 7.5,8.5 2.75,13.25 2,12.5 Z"
-       sodipodi:nodetypes="scccccccccccccccsccscssscccccc" />
+       sodipodi:nodetypes="scccccccccccccccsccscssscccccc"
+       inkscape:connector-curvature="0" />
+  </g>
+  <g
+     style="display:inline"
+     inkscape:groupmode="layer"
+     id="g5298"
+     inkscape:label="Double Down Chevron">
+    <path
+       style="color:#000000;font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:medium;line-height:normal;font-family:sans-serif;font-variant-ligatures:normal;font-variant-position:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-feature-settings:normal;text-indent:0;text-align:start;text-decoration:none;text-decoration-line:none;text-decoration-style:solid;text-decoration-color:#000000;letter-spacing:normal;word-spacing:normal;text-transform:none;writing-mode:lr-tb;direction:ltr;text-orientation:mixed;dominant-baseline:auto;baseline-shift:baseline;text-anchor:start;white-space:normal;shape-padding:0;clip-rule:nonzero;display:inline;overflow:visible;visibility:visible;opacity:1;isolation:auto;mix-blend-mode:normal;color-interpolation:sRGB;color-interpolation-filters:linearRGB;solid-color:#000000;solid-opacity:1;vector-effect:none;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:3;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1;color-rendering:auto;image-rendering:auto;shape-rendering:auto;text-rendering:auto;enable-background:accumulate"
+       d="M 3 0.5 L 1 2.5 L 8 9.5 L 15 2.5 L 13 0.5 L 8 5.5 L 3 0.5 z M 3 6.5 L 1 8.5 L 8 15.5 L 15 8.5 L 13 6.5 L 8 11.5 L 3 6.5 z "
+       id="path5300" />
   </g>
 </svg>
diff --git a/test/test-options-util.js b/test/test-options-util.js
index 7b9e6e4b..ce12bca9 100644
--- a/test/test-options-util.js
+++ b/test/test-options-util.js
@@ -135,7 +135,13 @@ function createProfileOptionsTestData1() {
             convertKatakanaToHiragana: 'variant',
             collapseEmphaticSequences: 'false'
         },
-        dictionaries: {},
+        dictionaries: {
+            'Test Dictionary': {
+                priority: 0,
+                enabled: true,
+                allowSecondarySearches: false
+            }
+        },
         parsing: {
             enableScanningParser: true,
             enableMecabParser: false,
@@ -401,7 +407,14 @@ function createProfileOptionsUpdatedTestData1() {
                 groups: []
             }
         },
-        dictionaries: {},
+        dictionaries: {
+            'Test Dictionary': {
+                priority: 0,
+                enabled: true,
+                allowSecondarySearches: false,
+                definitionsCollapsible: 'not-collapsible'
+            }
+        },
         parsing: {
             enableScanningParser: true,
             enableMecabParser: false,