feat: implement automatic tab grouping

browser/components/tabbrowser/content/tabbrowser.js

@@ -1382,6 +1382,9 @@
           },
         });
         newTab.dispatchEvent(event);
+        
+        // Notify observers for native tab grouping feature
+        Services.obs.notifyObservers(newTab, "browser-tab-activated");
 
         this._tabAttrModified(oldTab, ["selected"]);
         this._tabAttrModified(newTab, ["selected"]);
@@ -4037,6 +4040,9 @@
         detail: eventDetail || {},
       });
       tab.dispatchEvent(evt);
+      
+      // Notify observers for native tab grouping feature
+      Services.obs.notifyObservers(tab, "browser-tab-created");
     }
 
     /**
@@ -5013,6 +5019,8 @@
     }
 
     _endRemoveTab(aTab) {
+      // Notify observers for native tab grouping feature
+      Services.obs.notifyObservers(aTab, "browser-tab-removed");
       if (!aTab || !aTab._endRemoveArgs) {
         return;
       }
@@ -7220,6 +7228,10 @@
         // Intentional fallthrough
         case "deactivate":
           this.selectedTab.updateLastSeenActive();
+          // Notify observers for native tab grouping feature
+          if (aEvent.type === "activate") {
+            Services.obs.notifyObservers(null, "browser-window-focus-changed");
+          }
           break;
       }
     }

browser/installer/package-manifest.in

@@ -271,6 +271,7 @@
 @RESPATH@/browser/defaults/settings
 ; Waterfox preference files
 @RESPATH@/browser/@PREF_DIR@/prefs-lepton.js
+@RESPATH@/browser/@PREF_DIR@/prefs-tabgroups.js
 
 # channel-prefs.js has been removed on macOS.
 #ifndef XP_MACOSX

waterfox/browser/components/WaterfoxGlue.sys.mjs

@@ -15,6 +15,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
   PrivateTab: "resource:///modules/PrivateTab.sys.mjs",
   StatusBar: "resource:///modules/StatusBar.sys.mjs",
   TabFeatures: "resource:///modules/TabFeatures.sys.mjs",
+  TabGrouping: "resource:///modules/TabGrouping.sys.mjs",
   setTimeout: "resource://gre/modules/Timer.sys.mjs",
   UICustomizations: "resource:///modules/UICustomizations.sys.mjs",
 });
@@ -75,6 +76,9 @@ export const WaterfoxGlue = {
     this.addAddonListener();
     // Register about:cfg
     lazy.AboutPages.init();
+
+    // Initialize automatic tab grouping
+    lazy.TabGrouping.init();
   },
 
   async _setPrefObservers() {
@@ -215,6 +219,9 @@ export const WaterfoxGlue = {
         this._beforeUIStartup();
         this._delayedTasks();
         break;
+      case "quit-application-granted":
+        this.shutdown();
+        break;
     }
   },
 
@@ -406,6 +413,11 @@ export const WaterfoxGlue = {
     }
   },
 
+  shutdown() {
+    // Shutdown TabGrouping
+    lazy.TabGrouping.shutdown();
+  },
+
   updateCustomStylesheets(addon) {
     if (addon.type === "theme") {
       // If any theme and WF on any theme, reload stylesheets for every theme enable.

waterfox/browser/components/moz.build

@@ -14,6 +14,7 @@ DIRS += [
     "search",
     "statusbar",
     "tabfeatures",
+    "tabgrouping",
     "uicustomizations",
     "utils",
 ]

waterfox/browser/components/tabgrouping/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 David Demri
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the “Software”), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

waterfox/browser/components/tabgrouping/README.md

@@ -0,0 +1,58 @@
+# Automatic Tab Grouping Feature
+
+This feature is inspired by the Firefox WebExtension "New Tab Same Group" by onlybets.
+(Source: https://github.com/onlybets/firefox-addon-new-tab-same-group/blob/main/README.md)
+
+This module implements automatic tab grouping functionality, which automatically adds new tabs to the same group as the currently active tab.
+
+## Features
+
+- **Automatic Grouping**: When enabled, new tabs are automatically added to the same group as the source tab (the tab that was active when the new tab was created).
+
+- **Configurable Placement**: Users can choose where new tabs appear within the group:
+  - After the source tab (default)
+  - At the beginning of the group
+  - At the end of the group
+
+- **Optional Delay**: Users can enable a 1-second delay before grouping occurs, allowing them to cancel the operation if desired.
+
+- **Keyboard Shortcut**: When delay is enabled, users can press a keyboard shortcut (default: Ctrl+` on Windows/Linux, Alt+` on macOS) to cancel pending grouping operations.
+
+- **Bypass Shortcut**: Press Alt+Shift+T to open a new tab in the standard way (no grouping). This can be configured via preferences.
+
+- **Smart Tab Tracking**: The feature maintains a history of active tabs to handle edge cases where the source tab might not be immediately available.
+
+## Implementation
+
+The feature consists of:
+
+1. **TabGrouping.sys.mjs**: Core module that handles all the grouping logic
+2. **Preferences**: User-configurable settings with defaults
+3. **UI Overlays**: Integration with the preferences UI
+4. **Localization**: User-facing strings in tabgrouping.ftl
+
+## Preferences
+
+- `browser.tabs.autoGroupNewTabs`: Enable/disable the feature (default: true)
+- `browser.tabs.autoGroupNewTabs.placement`: Tab placement mode (default: "after")
+- `browser.tabs.autoGroupNewTabs.delayEnabled`: Enable grouping delay (default: false)
+- `browser.tabs.autoGroupNewTabs.delayMs`: Delay duration in milliseconds (default: 1000)
+- `browser.tabs.autoGroupNewTabs.cancelShortcut`: Keyboard shortcut to cancel (platform-specific default)
+- `browser.tabs.autoGroupNewTabs.bypassShortcut`: Keyboard shortcut to open a standard new tab without grouping (default: "Alt+Shift+T")
+
+## Architecture
+
+The module:
+- Listens for tab creation events via observer notifications
+- Tracks active tab history to determine the appropriate source tab
+- Manages pending grouping operations with timers
+- Handles keyboard shortcuts dynamically when delay is enabled
+- Integrates with the existing tab group infrastructure in tabbrowser.js
+
+## Usage
+
+The feature is automatically initialized when the browser starts via WaterfoxGlue.sys.mjs.
+
+This project contains code under two licenses:
+- Original implementation: MIT License (see LICENSE)
+- Rewritten portions: Mozilla Public License 2.0

waterfox/browser/components/tabgrouping/moz.build

@@ -0,0 +1,13 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXTRA_JS_MODULES += [
+    "TabGrouping.sys.mjs",
+]
+
+JS_PREFERENCE_PP_FILES += [
+    "prefs-tabgroups.js",
+]

waterfox/browser/components/tabgrouping/prefs-tabgroups.js

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Default preferences for automatic tab grouping feature
+
+// Enable automatic tab grouping
+pref("browser.tabs.autoGroupNewTabs", false);
+
+// Placement mode for new tabs in groups
+// Options: "after" (after source tab), "first" (beginning of group), "last" (end of group)
+pref("browser.tabs.autoGroupNewTabs.placement", "after");
+
+// Enable delay before grouping (allows user to cancel)
+pref("browser.tabs.autoGroupNewTabs.delayEnabled", false);
+
+// Delay in milliseconds before grouping occurs
+pref("browser.tabs.autoGroupNewTabs.delayMs", 1000);
+
+// Keyboard shortcut to cancel pending grouping
+// Default: Ctrl+` on Windows/Linux, Option+` on macOS
+#ifdef XP_MACOSX
+pref("browser.tabs.autoGroupNewTabs.cancelShortcut", "Option+`");
+#else
+pref("browser.tabs.autoGroupNewTabs.cancelShortcut", "Ctrl+`");
+#endif
+
+// Keyboard shortcut to open a standard new tab (bypass grouping)
+// Default: Alt+Shift+T (Windows/Linux), Option+Shift+T (macOS)
+#ifdef XP_MACOSX
+pref("browser.tabs.autoGroupNewTabs.bypassShortcut", "Option+Shift+T");
+#else
+pref("browser.tabs.autoGroupNewTabs.bypassShortcut", "Alt+Shift+T");
+#endif
+
+// Enable verbose debug logging for TabGrouping
+pref("browser.tabs.autoGroupNewTabs.debugLog", false);
+
+// Grace period after session restore before resuming auto-grouping (ms)
+pref("browser.tabs.autoGroupNewTabs.resumeGraceMs", 1000);