3 files changed, 40 insertions, 14 deletions
diff --git a/ext/js/background/backend.js b/ext/js/background/backend.js
index 565f4abf..755010a3 100644
--- a/ext/js/background/backend.js
+++ b/ext/js/background/backend.js
@@ -2099,20 +2099,12 @@ class Backend {
     }
 
     async _openWelcomeGuidePageOnce() {
-        if (isObject(chrome.storage) && isObject(chrome.storage.session)) {
-            // Chrome
-            chrome.storage.session.get(['openedWelcomePage']).then((result) => {
-                if (!result.openedWelcomePage) {
-                    this._openWelcomeGuidePage();
-                    chrome.storage.session.set({'openedWelcomePage': true});
-                }
-            });
-        } else {
-            // Firefox (storage.session is not supported yet)
-            // NOTE: This means that the welcome page will repeatedly open in Firefox
-            // until they support storage.session.
-            this._openWelcomeGuidePage();
-        }
+        chrome.storage.session.get(['openedWelcomePage']).then((result) => {
+            if (!result.openedWelcomePage) {
+                this._openWelcomeGuidePage();
+                chrome.storage.session.set({'openedWelcomePage': true});
+            }
+        });
     }
 
     async _openWelcomeGuidePage() {
diff --git a/ext/js/data/options-util.js b/ext/js/data/options-util.js
index 7b050416..1f2ffb05 100644
--- a/ext/js/data/options-util.js
+++ b/ext/js/data/options-util.js
@@ -1001,6 +1001,33 @@ class OptionsUtil {
 
     async _updateVersion21(options) {
         await this._applyAnkiFieldTemplatesPatch(options, '/data/templates/anki-field-templates-upgrade-v21.handlebars');
+
+        let customTemplates = false;
+        for (const {options: profileOptions} of options.profiles) {
+            if (profileOptions.anki.fieldTemplates !== null) {
+                customTemplates = true;
+            }
+        }
+
+        if (customTemplates && isObject(chrome.storage)) {
+            chrome.storage.session.set({'needsCustomTemplatesWarning': true});
+            await this._createTab(chrome.runtime.getURL('/welcome.html'));
+            chrome.storage.session.set({'openedWelcomePage': true});
+        }
+
         return options;
     }
+
+    _createTab(url) {
+        return new Promise((resolve, reject) => {
+            chrome.tabs.create({url}, (tab) => {
+                const e = chrome.runtime.lastError;
+                if (e) {
+                    reject(new Error(e.message));
+                } else {
+                    resolve(tab);
+                }
+            });
+        });
+    }
 }
diff --git a/ext/js/pages/welcome-main.js b/ext/js/pages/welcome-main.js
index 521ce2c2..8039dae5 100644
--- a/ext/js/pages/welcome-main.js
+++ b/ext/js/pages/welcome-main.js
@@ -58,6 +58,13 @@ async function setupGenericSettingsController(genericSettingController) {
 
         setupEnvironmentInfo();
 
+        chrome.storage.session.get({'needsCustomTemplatesWarning': false}).then((result) => {
+            if (result.needsCustomTemplatesWarning) {
+                document.documentElement.dataset.warnCustomTemplates = 'true';
+                chrome.storage.session.remove(['needsCustomTemplatesWarning']);
+            }
+        });
+
         const preparePromises = [];
 
         const modalController = new ModalController();