fix: Make sure drop indicator is under the last item when newtab button is below, b=no-bug, c=common

This reverts commit 956841a76e.

README.md

@@ -34,8 +34,8 @@ Zen is a firefox-based browser with the aim of pushing your productivity to a ne
 
 ### Firefox Versions
 
-- [`Release`](https://zen-browser.app/download) - Is currently built using Firefox version `147.0.1`! 🚀
+- [`Release`](https://zen-browser.app/download) - Is currently built using Firefox version `147.0.2`! 🚀
-- [`Twilight`](https://zen-browser.app/download?twilight) - Is currently built using Firefox version `RC 147.0.1`!
+- [`Twilight`](https://zen-browser.app/download?twilight) - Is currently built using Firefox version `RC 147.0.2`!
 
 ### Contributing
 

build/firefox-cache/l10n-last-commit-hash

@@ -1 +1 @@
-783b222b1b93fb9e8c52eb57558ef7f07bca6e7e
+7712a9ac90683965f71be525fe2827467632715d

build/flatpak/app.zen_browser.zen.yml.template

@@ -20,7 +20,6 @@ finish-args:
   - --socket=cups
   - --persist=.zen
   - --env=DICPATH=/usr/share/hunspell
-  - --filesystem=xdg-config/gtk-3.0:ro
   - --filesystem=xdg-download:rw
   - --filesystem=/run/.heim_org.h5l.kcm-socket
   - --filesystem=xdg-run/speech-dispatcher:ro

build/windows/sign.ps1

@@ -148,7 +148,7 @@ function SignAndPackage($name) {
         $env:WIN32_REDIST_DIR="$PWD\win-cross\vs2022\VC\Redist\MSVC\14.38.33135\x64\Microsoft.VC143.CRT"
     }
 
-    $env:MAR="..\\build\\winsign\\mar.exe"
+    $env:MAR="..\\build\\windows\\mar.exe"
     if ($name -eq "arm64") {
         $env:SURFER_COMPAT="aarch64"
     } else {

locales/en-US/browser/browser/preferences/zen-preferences.ftl

@@ -53,8 +53,8 @@ category-zen-workspaces =
     .tooltiptext = { pane-zen-tabs-title }
 pane-settings-workspaces-title = Workspaces
 
-zen-tabs-unloader-enabled =
+zen-tabs-select-recently-used-on-close =
-    .label = Enable Tab Unloader
+    .label = When closing a tab, switch to the most recently used tab instead of the next tab
 
 zen-tabs-close-on-back-with-no-history =
     .label = Close tab and switch to its owner tab (or most recently used tab) when going back with no history

locales/en-US/browser/browser/zen-menubar.ftl

@@ -23,4 +23,4 @@ zen-menubar-appearance-dark =
     .label = Dark
 
 zen-menubar-new-unsynced-window =
-    .label = New Blank Window
+    .label = New blank window

prefs/zen/session-store.yaml

@@ -6,7 +6,10 @@
   value: true
 
 - name: zen.session-store.log
-  value: "@IS_TWILIGHT@"
+  value: true
 
 - name: zen.session-store.restore-unsynced-windows
   value: true
+
+- name: browser.sessionstore.max_windows_undo
+  value: 2

prefs/zen/workspaces.yaml

@@ -33,7 +33,7 @@
   value: true
 
 - name: zen.workspaces.dnd-switch-padding
-  value: 4
+  value: 5
 
 - name: zen.workspaces.debug
   value: "@cond"

prefs/zen/zen.yaml

@@ -30,7 +30,7 @@
   value: 20 # Percentage of folder height to trigger dragover
 
 - name: zen.tabs.dnd-switch-space-delay
-  value: 1000 # milliseconds
+  value: 800 # milliseconds
 
 - name: zen.ctrlTab.show-pending-tabs
   value: false

src/browser/components/preferences/zen-settings.js

@@ -1193,6 +1193,11 @@ Preferences.addAll([
     type: "bool",
     default: false,
   },
+  {
+    id: "zen.tabs.select-recently-used-on-close",
+    type: "bool",
+    default: true,
+  },
 ]);
 
 Preferences.addSetting({

src/browser/components/preferences/zenTabsManagement.inc.xhtml

@@ -37,15 +37,10 @@
             class="description-deemphasized"
             data-l10n-id="zen-tabs-cycle-by-attribute-warning"
             hidden="true"/>
+      <checkbox data-l10n-id="zen-tabs-select-recently-used-on-close"
+            preference="zen.tabs.select-recently-used-on-close"/>
 </groupbox>
 
-<hbox id="zenTabsUnloadCategory"
-      class="subcategory"
-      hidden="true"
-      data-category="paneZenTabManagement">
-<html:h1 data-l10n-id="pane-zen-tabs-unloader-title"/>
-</hbox>
-
 <hbox id="zenPinnedTabsManagerCategory"
       class="subcategory"
       hidden="true"

src/browser/components/sessionstore/SessionStore-sys-mjs.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/sessionstore/SessionStore.sys.mjs b/browser/components/sessionstore/SessionStore.sys.mjs
-index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2e8fe19ff 100644
+index 2a055f0c5f34f0a2667f659185120c07d38f4e41..2f63071f78782dbc30bde25b3bcaa96faedf6f0b 100644
 --- a/browser/components/sessionstore/SessionStore.sys.mjs
 +++ b/browser/components/sessionstore/SessionStore.sys.mjs
 @@ -127,6 +127,9 @@ const TAB_EVENTS = [
@@ -54,6 +54,15 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
      let tabbrowser = aWindow.gBrowser;
  
      // add tab change listeners to all already existing tabs
+@@ -2076,7 +2085,7 @@ var SessionStoreInternal = {
+     let isTaskbarTab = this._windows[aWindow.__SSi].isTaskbarTab;
+     // A regular window is not a private window, taskbar tab window, or popup window
+     let isRegularWindow =
+-      !isPrivateWindow && !isTaskbarTab && aWindow.toolbar.visible;
++      !isPrivateWindow && !isTaskbarTab && aWindow.toolbar.visible && !this._windows[aWindow.__SSi].isZenUnsynced;
+ 
+     // perform additional initialization when the first window is loading
+     if (lazy.RunState.isStopped) {
 @@ -2131,6 +2140,7 @@ var SessionStoreInternal = {
            null,
            "sessionstore-one-or-no-tab-restored"
@@ -95,36 +104,56 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
  
      TAB_EVENTS.forEach(function (aEvent) {
        tabbrowser.tabContainer.removeEventListener(aEvent, this, true);
-@@ -2491,7 +2509,7 @@ var SessionStoreInternal = {
+@@ -2434,7 +2452,7 @@ var SessionStoreInternal = {
+ 
+       let isLastRegularWindow =
+         Object.values(this._windows).filter(
+-          wData => !wData.isPrivate && !wData.isTaskbarTab
++          wData => !wData.isPrivate && !wData.isTaskbarTab && !wData.isZenUnsynced
+         ).length == 1;
+       this._log.debug(
+         `onClose, closing window isLastRegularWindow? ${isLastRegularWindow}`
+@@ -2491,8 +2509,8 @@ var SessionStoreInternal = {
        // 2) Flush the window.
        // 3) When the flush is complete, revisit our decision to store the window
        //    in _closedWindows, and add/remove as necessary.
 -      if (!winData.isPrivate && !winData.isTaskbarTab) {
+-        this.maybeSaveClosedWindow(winData, isLastWindow);
 +      if (!winData.isPrivate && !winData.isTaskbarTab && !winData.isZenUnsynced) {
-         this.maybeSaveClosedWindow(winData, isLastWindow);
++        this.maybeSaveClosedWindow(winData, isLastWindow, isLastRegularWindow);
        }
  
-@@ -2512,7 +2530,8 @@ var SessionStoreInternal = {
+       completionPromise = lazy.TabStateFlusher.flushWindow(aWindow).then(() => {
+@@ -2512,8 +2530,9 @@ var SessionStoreInternal = {
  
          // Save non-private windows if they have at
          // least one saveable tab or are the last window.
 -        if (!winData.isPrivate && !winData.isTaskbarTab) {
+-          this.maybeSaveClosedWindow(winData, isLastWindow);
 +        lazy.ZenWindowSync.on_WindowCloseAndBrowserFlushed(browsers);
 +        if (!winData.isPrivate && !winData.isTaskbarTab && !winData.isZenUnsynced) {
-           this.maybeSaveClosedWindow(winData, isLastWindow);
++          this.maybeSaveClosedWindow(winData, isLastWindow, isLastRegularWindow);
  
            if (!isLastWindow && winData.closedId > -1) {
-@@ -2608,6 +2627,9 @@ var SessionStoreInternal = {
+             this._addClosedAction(
+@@ -2589,7 +2608,7 @@ var SessionStoreInternal = {
+    *        to call this method again asynchronously (for example, after
+    *        a window flush).
+    */
+-  maybeSaveClosedWindow(winData, isLastWindow) {
++  maybeSaveClosedWindow(winData, isLastWindow, isLastRegularWindow = false) {
+     // Make sure SessionStore is still running, and make sure that we
+     // haven't chosen to forget this window.
+     if (
+@@ -2606,6 +2625,7 @@ var SessionStoreInternal = {
+       // _closedWindows from a previous call to this function.
+       let winIndex = this._closedWindows.indexOf(winData);
        let alreadyStored = winIndex != -1;
++      lazy.ZenSessionStore.maybeSaveClosedWindow(winData, isLastRegularWindow);
        // If sidebar command is truthy, i.e. sidebar is open, store sidebar settings
        let shouldStore = hasSaveableTabs || isLastWindow;
-+      lazy.ZenSessionStore.maybeSaveClosedWindow(winData, isLastWindow);
-+      // TODO: Do we want to store closed Zen windows? All of them are synced anyways
-+      shouldStore = false;
  
-       if (shouldStore && !alreadyStored) {
+@@ -3408,7 +3428,7 @@ var SessionStoreInternal = {
-         let index = this._closedWindows.findIndex(win => {
-@@ -3408,7 +3430,7 @@ var SessionStoreInternal = {
      if (!isPrivateWindow && tabState.isPrivate) {
        return;
      }
@@ -133,7 +162,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
        return;
      }
  
-@@ -4129,6 +4151,12 @@ var SessionStoreInternal = {
+@@ -4129,6 +4149,12 @@ var SessionStoreInternal = {
          Math.min(tabState.index, tabState.entries.length)
        );
        tabState.pinned = false;
@@ -146,7 +175,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
  
        if (inBackground === false) {
          aWindow.gBrowser.selectedTab = newTab;
-@@ -4565,6 +4593,8 @@ var SessionStoreInternal = {
+@@ -4565,6 +4591,8 @@ var SessionStoreInternal = {
        // Append the tab if we're opening into a different window,
        tabIndex: aSource == aTargetWindow ? pos : Infinity,
        pinned: state.pinned,
@@ -155,7 +184,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
        userContextId: state.userContextId,
        skipLoad: true,
        preferredRemoteType,
-@@ -5414,7 +5444,7 @@ var SessionStoreInternal = {
+@@ -5414,7 +5442,7 @@ var SessionStoreInternal = {
  
      for (let i = tabbrowser.pinnedTabCount; i < tabbrowser.tabs.length; i++) {
        let tab = tabbrowser.tabs[i];
@@ -164,7 +193,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
          removableTabs.push(tab);
        }
      }
-@@ -5525,7 +5555,7 @@ var SessionStoreInternal = {
+@@ -5525,7 +5553,7 @@ var SessionStoreInternal = {
  
      // collect the data for all windows
      for (ix in this._windows) {
@@ -173,7 +202,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
          // window data is still in _statesToRestore
          continue;
        }
-@@ -5668,11 +5698,12 @@ var SessionStoreInternal = {
+@@ -5668,11 +5696,12 @@ var SessionStoreInternal = {
      }
  
      let tabbrowser = aWindow.gBrowser;
@@ -187,7 +216,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
      // update the internal state data for this window
      for (let tab of tabs) {
        if (tab == aWindow.FirefoxViewHandler.tab) {
-@@ -5683,6 +5714,9 @@ var SessionStoreInternal = {
+@@ -5683,6 +5712,9 @@ var SessionStoreInternal = {
        tabsData.push(tabData);
      }
  
@@ -197,7 +226,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
      // update tab group state for this window
      winData.groups = [];
      for (let tabGroup of aWindow.gBrowser.tabGroups) {
-@@ -5695,7 +5729,7 @@ var SessionStoreInternal = {
+@@ -5695,7 +5727,7 @@ var SessionStoreInternal = {
      // a window is closed, point to the first item in the tab strip instead (it will never be the Firefox View tab,
      // since it's only inserted into the tab strip after it's selected).
      if (aWindow.FirefoxViewHandler.tab?.selected) {
@@ -206,7 +235,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
        winData.title = tabbrowser.tabs[0].label;
      }
      winData.selected = selectedIndex;
-@@ -5810,8 +5844,8 @@ var SessionStoreInternal = {
+@@ -5810,8 +5842,8 @@ var SessionStoreInternal = {
      // selectTab represents.
      let selectTab = 0;
      if (overwriteTabs) {
@@ -217,7 +246,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
        selectTab = Math.min(selectTab, winData.tabs.length);
      }
  
-@@ -5833,6 +5867,7 @@ var SessionStoreInternal = {
+@@ -5833,6 +5865,7 @@ var SessionStoreInternal = {
      if (overwriteTabs) {
        for (let i = tabbrowser.browsers.length - 1; i >= 0; i--) {
          if (!tabbrowser.tabs[i].selected) {
@@ -225,7 +254,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
            tabbrowser.removeTab(tabbrowser.tabs[i]);
          }
        }
-@@ -5866,6 +5901,12 @@ var SessionStoreInternal = {
+@@ -5866,6 +5899,12 @@ var SessionStoreInternal = {
          savedTabGroup => !openTabGroupIdsInWindow.has(savedTabGroup.id)
        );
      }
@@ -238,7 +267,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
  
      // Move the originally open tabs to the end.
      if (initialTabs) {
-@@ -6419,6 +6460,25 @@ var SessionStoreInternal = {
+@@ -6419,6 +6458,25 @@ var SessionStoreInternal = {
  
      // Most of tabData has been restored, now continue with restoring
      // attributes that may trigger external events.
@@ -264,7 +293,17 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
  
      if (tabData.pinned) {
        tabbrowser.pinTab(tab);
-@@ -7343,7 +7403,7 @@ var SessionStoreInternal = {
+@@ -6567,6 +6625,9 @@ var SessionStoreInternal = {
+         aWindow.gURLBar.readOnly = false;
+       }
+     }
++    if (aWinData.isZenUnsynced) {
++      this._windows[aWindow.__SSi].isZenUnsynced = true;
++    }
+ 
+     let promiseParts = Promise.withResolvers();
+     aWindow.setTimeout(() => {
+@@ -7343,7 +7404,7 @@ var SessionStoreInternal = {
  
        let groupsToSave = new Map();
        for (let tIndex = 0; tIndex < window.tabs.length; ) {
@@ -273,7 +312,7 @@ index 2a055f0c5f34f0a2667f659185120c07d38f4e41..cd350d9e787c1ef0d1dffcb7d872b9c2
            // Adjust window.selected
            if (tIndex + 1 < window.selected) {
              window.selected -= 1;
-@@ -7358,7 +7418,7 @@ var SessionStoreInternal = {
+@@ -7358,7 +7419,7 @@ var SessionStoreInternal = {
            );
            // We don't want to increment tIndex here.
            continue;

src/browser/components/tabbrowser/content/tabbrowser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
-index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a1417570d4f1266 100644
+index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..7f759f43a4aa1e0d96f8003a50c5df269ec4a131 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -398,6 +398,7 @@
@@ -119,7 +119,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        aTab.setAttribute("pinned", "true");
        this._updateTabBarForPinnedTabs();
-@@ -931,11 +994,18 @@
+@@ -931,11 +994,19 @@
        }
  
        this.#handleTabMove(aTab, () => {
@@ -133,13 +133,14 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          // and back into arrowscrollbox.
          aTab.removeAttribute("pinned");
 -        this.tabContainer.arrowScrollbox.prepend(aTab);
++        aTab.removeAttribute("zen-essential");
 +        if (!handled) {
 +          gZenWorkspaces.activeWorkspaceStrip.prepend(aTab);
 +        }
        });
  
        aTab.style.marginInlineStart = "";
-@@ -1112,6 +1182,9 @@
+@@ -1112,6 +1183,9 @@
  
        let LOCAL_PROTOCOLS = ["chrome:", "about:", "resource:", "data:"];
  
@@ -149,7 +150,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (
          aIconURL &&
          !LOCAL_PROTOCOLS.some(protocol => aIconURL.startsWith(protocol))
-@@ -1121,6 +1194,9 @@
+@@ -1121,6 +1195,9 @@
          );
          return;
        }
@@ -159,7 +160,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        let browser = this.getBrowserForTab(aTab);
        browser.mIconURL = aIconURL;
-@@ -1393,7 +1469,6 @@
+@@ -1393,7 +1470,6 @@
  
        // Preview mode should not reset the owner
        if (!this._previewMode && !oldTab.selected) {
@@ -167,7 +168,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        }
  
        let lastRelatedTab = this._lastRelatedTabMap.get(oldTab);
-@@ -1484,6 +1559,7 @@
+@@ -1484,6 +1560,7 @@
        if (!this._previewMode) {
          newTab.recordTimeFromUnloadToReload();
          newTab.updateLastAccessed();
@@ -175,7 +176,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          oldTab.updateLastAccessed();
          // if this is the foreground window, update the last-seen timestamps.
          if (this.ownerGlobal == BrowserWindowTracker.getTopWindow()) {
-@@ -1636,6 +1712,9 @@
+@@ -1636,6 +1713,9 @@
        }
  
        let activeEl = document.activeElement;
@@ -185,7 +186,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // If focus is on the old tab, move it to the new tab.
        if (activeEl == oldTab) {
          newTab.focus();
-@@ -1959,6 +2038,11 @@
+@@ -1959,6 +2039,11 @@
      }
  
      _setTabLabel(aTab, aLabel, { beforeTabOpen, isContentTitle, isURL } = {}) {
@@ -197,7 +198,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (!aLabel || aLabel.includes("about:reader?")) {
          return false;
        }
-@@ -2067,7 +2151,7 @@
+@@ -2067,7 +2152,7 @@
          newIndex = this.selectedTab._tPos + 1;
        }
  
@@ -206,7 +207,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          if (this.isTabGroupLabel(targetTab)) {
            throw new Error(
              "Replacing a tab group label with a tab is not supported"
-@@ -2342,6 +2426,7 @@
+@@ -2342,6 +2427,7 @@
        uriIsAboutBlank,
        userContextId,
        skipLoad,
@@ -214,7 +215,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
      } = {}) {
        let b = document.createXULElement("browser");
        // Use the JSM global to create the permanentKey, so that if the
-@@ -2415,8 +2500,7 @@
+@@ -2415,8 +2501,7 @@
          // we use a different attribute name for this?
          b.setAttribute("name", name);
        }
@@ -224,7 +225,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          b.setAttribute("transparent", "true");
        }
  
-@@ -2581,7 +2665,7 @@
+@@ -2581,7 +2666,7 @@
  
        let panel = this.getPanel(browser);
        let uniqueId = this._generateUniquePanelID();
@@ -233,7 +234,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        aTab.linkedPanel = uniqueId;
  
        // Inject the <browser> into the DOM if necessary.
-@@ -2640,8 +2724,8 @@
+@@ -2640,8 +2725,8 @@
        // If we transitioned from one browser to two browsers, we need to set
        // hasSiblings=false on both the existing browser and the new browser.
        if (this.tabs.length == 2) {
@@ -244,7 +245,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } else {
          aTab.linkedBrowser.browsingContext.hasSiblings = this.tabs.length > 1;
        }
-@@ -2828,7 +2912,6 @@
+@@ -2828,7 +2913,6 @@
              this.selectedTab = this.addTrustedTab(BROWSER_NEW_TAB_URL, {
                tabIndex: tab._tPos + 1,
                userContextId: tab.userContextId,
@@ -252,7 +253,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
                focusUrlBar: true,
              });
              resolve(this.selectedBrowser);
-@@ -2938,6 +3021,9 @@
+@@ -2938,6 +3022,9 @@
          schemelessInput,
          hasValidUserGestureActivation = false,
          textDirectiveUserActivation = false,
@@ -262,7 +263,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } = {}
      ) {
        // all callers of addTab that pass a params object need to pass
-@@ -2948,10 +3034,17 @@
+@@ -2948,10 +3035,17 @@
          );
        }
  
@@ -280,7 +281,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // If we're opening a foreground tab, set the owner by default.
        ownerTab ??= inBackground ? null : this.selectedTab;
  
-@@ -2959,6 +3052,7 @@
+@@ -2959,6 +3053,7 @@
        if (this.selectedTab.owner) {
          this.selectedTab.owner = null;
        }
@@ -288,7 +289,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        // Find the tab that opened this one, if any. This is used for
        // determining positioning, and inherited attributes such as the
-@@ -3011,6 +3105,22 @@
+@@ -3011,6 +3106,22 @@
            noInitialLabel,
            skipBackgroundNotify,
          });
@@ -311,7 +312,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          if (insertTab) {
            // Insert the tab into the tab container in the correct position.
            this.#insertTabAtIndex(t, {
-@@ -3019,6 +3129,7 @@
+@@ -3019,6 +3130,7 @@
              ownerTab,
              openerTab,
              pinned,
@@ -319,7 +320,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
              bulkOrderedOpen,
              tabGroup: tabGroup ?? openerTab?.group,
            });
-@@ -3037,6 +3148,7 @@
+@@ -3037,6 +3149,7 @@
            openWindowInfo,
            skipLoad,
            triggeringRemoteType,
@@ -327,7 +328,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          }));
  
          if (focusUrlBar) {
-@@ -3161,6 +3273,12 @@
+@@ -3161,6 +3274,12 @@
          }
        }
  
@@ -340,7 +341,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // Additionally send pinned tab events
        if (pinned) {
          this.#notifyPinnedStatus(t);
-@@ -3375,6 +3493,7 @@
+@@ -3375,6 +3494,7 @@
          isAdoptingGroup = false,
          isUserTriggered = false,
          telemetryUserCreateSource = "unknown",
@@ -348,7 +349,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } = {}
      ) {
        if (
-@@ -3385,9 +3504,6 @@
+@@ -3385,9 +3505,6 @@
              !this.isSplitViewWrapper(tabOrSplitView)
          )
        ) {
@@ -358,7 +359,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        }
  
        if (!color) {
-@@ -3408,9 +3524,14 @@
+@@ -3408,9 +3525,14 @@
          label,
          isAdoptingGroup
        );
@@ -375,7 +376,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        );
        group.addTabs(tabsAndSplitViews);
  
-@@ -3531,7 +3652,7 @@
+@@ -3531,7 +3653,7 @@
        }
  
        this.#handleTabMove(tab, () =>
@@ -384,7 +385,15 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        );
      }
  
-@@ -3746,6 +3867,7 @@
+@@ -3599,6 +3721,7 @@
+         color: group.color,
+         insertBefore: newTabs[0],
+         isAdoptingGroup: true,
++        forSplitView: group.hasAttribute('split-view-group'),
+       });
+     }
+ 
+@@ -3746,6 +3869,7 @@
          openWindowInfo,
          skipLoad,
          triggeringRemoteType,
@@ -392,7 +401,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        }
      ) {
        // If we don't have a preferred remote type (or it is `NOT_REMOTE`), and
-@@ -3815,6 +3937,7 @@
+@@ -3815,6 +3939,7 @@
            openWindowInfo,
            name,
            skipLoad,
@@ -400,7 +409,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          });
        }
  
-@@ -4003,7 +4126,7 @@
+@@ -4003,7 +4128,7 @@
          // Add a new tab if needed.
          if (!tab) {
            let createLazyBrowser =
@@ -409,7 +418,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
            let url = "about:blank";
            if (tabData.entries?.length) {
-@@ -4040,8 +4163,10 @@
+@@ -4040,8 +4165,10 @@
              insertTab: false,
              skipLoad: true,
              preferredRemoteType,
@@ -421,7 +430,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            if (select) {
              tabToSelect = tab;
            }
-@@ -4053,7 +4178,8 @@
+@@ -4053,7 +4180,8 @@
            this.pinTab(tab);
            // Then ensure all the tab open/pinning information is sent.
            this._fireTabOpen(tab, {});
@@ -431,7 +440,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            let { groupId } = tabData;
            const tabGroup = tabGroupWorkingData.get(groupId);
            // if a tab refers to a tab group we don't know, skip any group
-@@ -4067,7 +4193,10 @@
+@@ -4067,7 +4195,10 @@
                  tabGroup.stateData.id,
                  tabGroup.stateData.color,
                  tabGroup.stateData.collapsed,
@@ -443,7 +452,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
                );
                tabsFragment.appendChild(tabGroup.node);
              }
-@@ -4112,9 +4241,23 @@
+@@ -4112,9 +4243,23 @@
        // to remove the old selected tab.
        if (tabToSelect) {
          let leftoverTab = this.selectedTab;
@@ -459,15 +468,15 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
 +            gZenWorkspaces._initialTab._shouldRemove = true;
 +          }
 +        }
-       }
++      }
 +      else {
 +        gZenWorkspaces._tabToRemoveForEmpty = this.selectedTab;
-+      }
+       }
 +      this._hasAlreadyInitializedZenSessionStore = true;
  
        if (tabs.length > 1 || !tabs[0].selected) {
          this._updateTabsAfterInsert();
-@@ -4305,11 +4448,14 @@
+@@ -4305,11 +4450,14 @@
        if (ownerTab) {
          tab.owner = ownerTab;
        }
@@ -483,7 +492,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          if (
            !bulkOrderedOpen &&
            ((openerTab &&
-@@ -4321,7 +4467,7 @@
+@@ -4321,7 +4469,7 @@
            let lastRelatedTab =
              openerTab && this._lastRelatedTabMap.get(openerTab);
            let previousTab = lastRelatedTab || openerTab || this.selectedTab;
@@ -492,7 +501,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
              tabGroup = previousTab.group;
            }
            if (
-@@ -4337,7 +4483,7 @@
+@@ -4337,7 +4485,7 @@
                  previousTab.splitview
                ) + 1;
            } else if (previousTab.visible) {
@@ -501,7 +510,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            } else if (previousTab == FirefoxViewHandler.tab) {
              elementIndex = 0;
            }
-@@ -4365,14 +4511,14 @@
+@@ -4365,14 +4513,14 @@
        }
        // Ensure index is within bounds.
        if (tab.pinned) {
@@ -520,7 +529,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        if (pinned && !itemAfter?.pinned) {
          itemAfter = null;
-@@ -4385,7 +4531,7 @@
+@@ -4385,7 +4533,7 @@
  
        this.tabContainer._invalidateCachedTabs();
  
@@ -529,7 +538,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          if (
            (this.isTab(itemAfter) && itemAfter.group == tabGroup) ||
            this.isSplitViewWrapper(itemAfter)
-@@ -4416,7 +4562,11 @@
+@@ -4416,7 +4564,11 @@
          const tabContainer = pinned
            ? this.tabContainer.pinnedTabsContainer
            : this.tabContainer;
@@ -541,7 +550,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        }
  
        if (tab.group?.collapsed) {
-@@ -4431,6 +4581,7 @@
+@@ -4431,6 +4583,7 @@
        if (pinned) {
          this._updateTabBarForPinnedTabs();
        }
@@ -549,7 +558,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        TabBarVisibility.update();
      }
-@@ -4983,6 +5134,7 @@
+@@ -4983,6 +5136,7 @@
          telemetrySource,
        } = {}
      ) {
@@ -557,7 +566,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // When 'closeWindowWithLastTab' pref is enabled, closing all tabs
        // can be considered equivalent to closing the window.
        if (
-@@ -5072,6 +5224,7 @@
+@@ -5072,6 +5226,7 @@
          if (lastToClose) {
            this.removeTab(lastToClose, aParams);
          }
@@ -565,7 +574,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } catch (e) {
          console.error(e);
        }
-@@ -5110,6 +5263,12 @@
+@@ -5110,6 +5265,12 @@
          aTab._closeTimeNoAnimTimerId = Glean.browserTabclose.timeNoAnim.start();
        }
  
@@ -578,7 +587,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // Handle requests for synchronously removing an already
        // asynchronously closing tab.
        if (!animate && aTab.closing) {
-@@ -5124,6 +5283,9 @@
+@@ -5124,6 +5285,9 @@
        // state).
        let tabWidth = window.windowUtils.getBoundsWithoutFlushing(aTab).width;
        let isLastTab = this.#isLastTabInWindow(aTab);
@@ -588,7 +597,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (
          !this._beginRemoveTab(aTab, {
            closeWindowFastpath: true,
-@@ -5172,7 +5334,13 @@
+@@ -5172,7 +5336,13 @@
          // We're not animating, so we can cancel the animation stopwatch.
          Glean.browserTabclose.timeAnim.cancel(aTab._closeTimeAnimTimerId);
          aTab._closeTimeAnimTimerId = null;
@@ -603,7 +612,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          return;
        }
  
-@@ -5306,7 +5474,7 @@
+@@ -5306,7 +5476,7 @@
            closeWindowWithLastTab != null
              ? closeWindowWithLastTab
              : !window.toolbar.visible ||
@@ -612,7 +621,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
          if (closeWindow) {
            // We've already called beforeunload on all the relevant tabs if we get here,
-@@ -5330,6 +5498,7 @@
+@@ -5330,6 +5500,7 @@
  
          newTab = true;
        }
@@ -620,7 +629,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        aTab._endRemoveArgs = [closeWindow, newTab];
  
        // swapBrowsersAndCloseOther will take care of closing the window without animation.
-@@ -5370,13 +5539,7 @@
+@@ -5370,13 +5541,7 @@
        aTab._mouseleave();
  
        if (newTab) {
@@ -635,7 +644,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } else {
          TabBarVisibility.update();
        }
-@@ -5509,6 +5672,7 @@
+@@ -5509,6 +5674,7 @@
          this.tabs[i]._tPos = i;
        }
  
@@ -643,7 +652,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (!this._windowIsClosing) {
          // update tab close buttons state
          this.tabContainer._updateCloseButtons();
-@@ -5732,6 +5896,7 @@
+@@ -5732,6 +5898,7 @@
        }
  
        let excludeTabs = new Set(aExcludeTabs);
@@ -651,7 +660,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        // If this tab has a successor, it should be selectable, since
        // hiding or closing a tab removes that tab as a successor.
-@@ -5744,15 +5909,22 @@
+@@ -5744,15 +5911,22 @@
          !excludeTabs.has(aTab.owner) &&
          Services.prefs.getBoolPref("browser.tabs.selectOwnerOnClose")
        ) {
@@ -676,7 +685,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        let tab = this.tabContainer.findNextTab(aTab, {
          direction: 1,
          filter: _tab => remainingTabs.includes(_tab),
-@@ -5766,7 +5938,7 @@
+@@ -5766,7 +5940,7 @@
        }
  
        if (tab) {
@@ -685,7 +694,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        }
  
        // If no qualifying visible tab was found, see if there is a tab in
-@@ -5787,7 +5959,7 @@
+@@ -5787,7 +5961,7 @@
          });
        }
  
@@ -694,7 +703,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
      }
  
      _blurTab(aTab) {
-@@ -5798,7 +5970,7 @@
+@@ -5798,7 +5972,7 @@
       * @returns {boolean}
       *   False if swapping isn't permitted, true otherwise.
       */
@@ -703,7 +712,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // Do not allow transfering a private tab to a non-private window
        // and vice versa.
        if (
-@@ -5852,6 +6024,7 @@
+@@ -5852,6 +6026,7 @@
        // fire the beforeunload event in the process.  Close the other
        // window if this was its last tab.
        if (
@@ -711,7 +720,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          !remoteBrowser._beginRemoveTab(aOtherTab, {
            adoptedByTab: aOurTab,
            closeWindowWithLastTab: true,
-@@ -5863,7 +6036,7 @@
+@@ -5863,7 +6038,7 @@
        // If this is the last tab of the window, hide the window
        // immediately without animation before the docshell swap, to avoid
        // about:blank being painted.
@@ -720,7 +729,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (closeWindow) {
          let win = aOtherTab.ownerGlobal;
          win.windowUtils.suppressAnimation(true);
-@@ -5987,11 +6160,13 @@
+@@ -5987,11 +6162,13 @@
        }
  
        // Finish tearing down the tab that's going away.
@@ -734,7 +743,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
        this.setTabTitle(aOurTab);
  
-@@ -6193,10 +6368,10 @@
+@@ -6193,10 +6370,10 @@
        SessionStore.deleteCustomTabValue(aTab, "hiddenBy");
      }
  
@@ -747,7 +756,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          aTab.selected ||
          aTab.closing ||
          // Tabs that are sharing the screen, microphone or camera cannot be hidden.
-@@ -6254,7 +6429,8 @@
+@@ -6254,7 +6431,8 @@
       *
       * @param {MozTabbrowserTab|MozTabbrowserTabGroup|MozTabbrowserTabGroup.labelElement} aTab
       */
@@ -757,7 +766,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        if (this.tabs.length == 1) {
          return null;
        }
-@@ -6278,12 +6454,14 @@
+@@ -6278,12 +6456,14 @@
        }
  
        // tell a new window to take the "dropped" tab
@@ -773,7 +782,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
      }
  
      /**
-@@ -6388,7 +6566,7 @@
+@@ -6388,7 +6568,7 @@
       *   `true` if element is a `<tab-group>`
       */
      isTabGroup(element) {
@@ -782,7 +791,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
      }
  
      /**
-@@ -6473,8 +6651,8 @@
+@@ -6473,8 +6653,8 @@
        }
  
        // Don't allow mixing pinned and unpinned tabs.
@@ -793,7 +802,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } else {
          tabIndex = Math.max(tabIndex, this.pinnedTabCount);
        }
-@@ -6500,10 +6678,16 @@
+@@ -6500,10 +6680,16 @@
        this.#handleTabMove(
          element,
          () => {
@@ -812,7 +821,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            if (neighbor && this.isTab(element) && tabIndex > element._tPos) {
              neighbor.after(element);
            } else {
-@@ -6561,23 +6745,31 @@
+@@ -6561,23 +6747,31 @@
      #moveTabNextTo(element, targetElement, moveBefore = false, metricsContext) {
        if (this.isTabGroupLabel(targetElement)) {
          targetElement = targetElement.group;
@@ -850,7 +859,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        } else if (!element.pinned && targetElement && targetElement.pinned) {
          // If the caller asks to move an unpinned element next to a pinned
          // tab, move the unpinned element to be the first unpinned element
-@@ -6590,14 +6782,34 @@
+@@ -6590,14 +6784,34 @@
          //    move the tab group right before the first unpinned tab.
          // 4. Moving a tab group and the first unpinned tab is grouped:
          //    move the tab group right before the first unpinned tab's tab group.
@@ -886,7 +895,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          element.pinned
            ? this.tabContainer.pinnedTabsContainer
            : this.tabContainer;
-@@ -6606,7 +6818,7 @@
+@@ -6606,7 +6820,7 @@
          element,
          () => {
            if (moveBefore) {
@@ -895,7 +904,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            } else if (targetElement) {
              targetElement.after(element);
            } else {
-@@ -6676,10 +6888,10 @@
+@@ -6676,10 +6890,10 @@
       * @param {TabMetricsContext} [metricsContext]
       */
      moveTabToExistingGroup(aTab, aGroup, metricsContext) {
@@ -908,7 +917,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          return;
        }
        if (aTab.group && aTab.group.id === aGroup.id) {
-@@ -6751,6 +6963,7 @@
+@@ -6751,6 +6965,7 @@
  
        let state = {
          tabIndex: tab._tPos,
@@ -916,7 +925,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        };
        if (tab.visible) {
          state.elementIndex = tab.elementIndex;
-@@ -6777,7 +6990,7 @@
+@@ -6777,7 +6992,7 @@
        let changedTabGroup =
          previousTabState.tabGroupId != currentTabState.tabGroupId;
  
@@ -925,7 +934,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
          tab.dispatchEvent(
            new CustomEvent("TabMove", {
              bubbles: true,
-@@ -6818,6 +7031,10 @@
+@@ -6818,6 +7033,10 @@
  
        moveActionCallback();
  
@@ -936,11 +945,11 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        // Clear tabs cache after moving nodes because the order of tabs may have
        // changed.
        this.tabContainer._invalidateCachedTabs();
-@@ -6869,6 +7086,19 @@
+@@ -6869,6 +7088,18 @@
       *    The new tab in the current window, null if the tab couldn't be adopted.
       */
      adoptTab(aTab, { elementIndex, tabIndex, selectTab = false } = {}) {
-+      if (window.gZenWorkspaces.currentWindowIsSyncing === aTab.ownerGlobal.gZenWorkspaces.currentWindowIsSyncing) {
++      if (window.gZenWorkspaces.currentWindowIsSyncing && aTab.ownerGlobal.gZenWorkspaces?.currentWindowIsSyncing) {
 +        const tabId = aTab.id;
 +        const thisTab = window.gZenWindowSync.getItemFromWindow(window, tabId);
 +        if (thisTab) {
@@ -951,12 +960,11 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
 +          }
 +          return thisTab;
 +        }
-+        return;
 +      }
        // Swap the dropped tab with a new one we create and then close
        // it in the other window (making it seem to have moved between
        // windows). We also ensure that the tab we create to swap into has
-@@ -6910,6 +7140,8 @@
+@@ -6910,6 +7141,8 @@
          params.userContextId = aTab.getAttribute("usercontextid");
        }
        let newTab = this.addWebTab("about:blank", params);
@@ -965,7 +973,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
        let newBrowser = this.getBrowserForTab(newTab);
  
        aTab.container.tabDragAndDrop.finishAnimateTabMove();
-@@ -7718,7 +7950,7 @@
+@@ -7718,7 +7951,7 @@
              // preventDefault(). It will still raise the window if appropriate.
              break;
            }
@@ -974,7 +982,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            window.focus();
            aEvent.preventDefault();
            break;
-@@ -7735,7 +7967,6 @@
+@@ -7735,7 +7968,6 @@
          }
          case "TabGroupCollapse":
            aEvent.target.tabs.forEach(tab => {
@@ -982,7 +990,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            });
            break;
          case "TabGroupCreateByUser":
-@@ -7895,7 +8126,9 @@
+@@ -7895,7 +8127,9 @@
  
          let filter = this._tabFilters.get(tab);
          if (filter) {
@@ -992,7 +1000,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
  
            let listener = this._tabListeners.get(tab);
            if (listener) {
-@@ -8698,6 +8931,7 @@
+@@ -8698,6 +8932,7 @@
              aWebProgress.isTopLevel
            ) {
              this.mTab.setAttribute("busy", "true");
@@ -1000,7 +1008,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
              gBrowser._tabAttrModified(this.mTab, ["busy"]);
              this.mTab._notselectedsinceload = !this.mTab.selected;
            }
-@@ -8778,6 +9012,7 @@
+@@ -8778,6 +9013,7 @@
          // known defaults. Note we use the original URL since about:newtab
          // redirects to a prerendered page.
          const shouldRemoveFavicon =
@@ -1008,7 +1016,7 @@ index 0eaca7a58e0026237b71b2ad515efe84d9e8c779..9c1fa86151f3d5896c45fef31a141757
            !this.mBrowser.mIconURL &&
            !ignoreBlank &&
            !(originalLocation.spec in FAVICON_DEFAULTS);
-@@ -9803,7 +10038,7 @@ var TabContextMenu = {
+@@ -9803,7 +10039,7 @@ var TabContextMenu = {
      );
      contextUnpinSelectedTabs.hidden =
        !this.contextTab.pinned || !this.multiselected;

src/browser/themes/shared/tabbrowser/content-area-css.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/themes/shared/tabbrowser/content-area.css b/browser/themes/shared/tabbrowser/content-area.css
-index b00139d7af878326ff303c08d5ddd47501b8c7db..52bad3e978004f3322f3d504cbd663e7b620b69f 100644
+index b00139d7af878326ff303c08d5ddd47501b8c7db..7361a5e98d6ea372f6fdc583d90044d276cfb81b 100644
 --- a/browser/themes/shared/tabbrowser/content-area.css
 +++ b/browser/themes/shared/tabbrowser/content-area.css
 @@ -90,7 +90,6 @@
@@ -32,7 +32,7 @@ index b00139d7af878326ff303c08d5ddd47501b8c7db..52bad3e978004f3322f3d504cbd663e7
  .dialogOverlay[topmost="true"],
  #window-modal-dialog::backdrop {
 -  background-color: var(--dialog-backdrop-color);
-+  background-color: light-dark(rgba(255, 255, 255, .2), rgba(0, 0, 0, .2));
++  background-color: light-dark(rgba(255, 255, 255, .3), rgba(0, 0, 0, .3));
  }
  
  .dialogOverlay[hideContent="true"][topmost="true"] {

src/zen/common/modules/ZenMenubar.mjs

@@ -24,6 +24,7 @@ export class nsZenMenuBar {
     this.#initViewMenu();
     this.#initSpacesMenu();
     this.#initAppMenu();
+    this.#hideWindowRestoreMenus();
   }
 
   #initViewMenu() {
@@ -121,4 +122,15 @@ export class nsZenMenuBar {
                 command="cmd_zenNewNavigatorUnsynced"/>`)
     );
   }
+
+  #hideWindowRestoreMenus() {
+    if (!Services.prefs.getBoolPref("zen.window-sync.enabled", true)) {
+      return;
+    }
+    const itemsToHide = ["appMenuRecentlyClosedWindows", "historyUndoWindowMenu"];
+    for (const id of itemsToHide) {
+      const element = PanelMultiView.getViewNode(document, id);
+      element.setAttribute("hidden", "true");
+    }
+  }
 }

src/zen/common/modules/ZenStartup.mjs

@@ -87,7 +87,6 @@ class ZenStartup {
       await delayedStartupPromise;
       await SessionStore.promiseAllWindowsRestored;
       delete gZenUIManager.promiseInitialized;
-      this.#initSearchBar();
       gZenCompactModeManager.init();
       // Fix for https://github.com/zen-browser/desktop/issues/7605, specially in compact mode
       if (gURLBar.hasAttribute("breakout-extend")) {
@@ -154,11 +153,6 @@ class ZenStartup {
     }
   }
 
-  #initSearchBar() {
-    // Only focus the url bar
-    gURLBar.focus();
-  }
-
   #checkForWelcomePage() {
     if (!Services.prefs.getBoolPref("zen.welcome-screen.seen", false)) {
       Services.prefs.setBoolPref("zen.welcome-screen.seen", true);

src/zen/common/modules/ZenUIManager.mjs

@@ -891,8 +891,8 @@ window.gZenVerticalTabsManager = {
             marginBottom: isLastItem() ? ["0px", "0px"] : [transform, "0px"],
           },
           {
-            duration: 0.11,
+            duration: 0.075,
-            easing: "ease-out",
+            easing: "easeOut",
           }
         )
         .then(() => {})
@@ -913,8 +913,8 @@ window.gZenVerticalTabsManager = {
             filter: ["blur(1px)", "blur(0px)"],
           },
           {
-            duration: 0.11,
+            duration: 0.075,
-            easing: "ease-out",
+            easing: "easeOut",
           }
         )
         .then(() => {})
@@ -949,7 +949,7 @@ window.gZenVerticalTabsManager = {
       },
       {
         duration: 0.075,
-        easing: "ease-out",
+        easing: "easeOut",
       }
     );
   },
@@ -1362,7 +1362,7 @@ window.gZenVerticalTabsManager = {
         // Check if name is blank, reset if so
         // Always remove, so we can always rename and if it's empty,
         // it will reset to the original name anyway
-        if (hasChanged) {
+        if (hasChanged || (this._tabEdited.zenStaticLabel && newName)) {
           this._tabEdited.zenStaticLabel = newName;
           gBrowser._setTabLabel(this._tabEdited, newName);
           gZenUIManager.showToast("zen-tabs-renamed");

src/zen/common/styles/zen-browser-container.css

@@ -61,6 +61,9 @@
 
 .zen-pseudo-browser-image {
   position: absolute;
+  transform: scale(1);
+  width: 100%;
+  height: 100%;
   inset: 0;
   opacity: 0.4;
   pointer-events: none;

src/zen/common/styles/zen-theme.css

@@ -142,7 +142,7 @@
 
   --zen-toolbar-element-bg: light-dark(
     color-mix(in oklch, var(--toolbox-textcolor) 10%, transparent),
-    color-mix(in oklch, var(--toolbox-textcolor) 12.5%, transparent)
+    color-mix(in oklch, var(--toolbox-textcolor) 15%, transparent)
   );
 
   --zen-toolbar-element-bg-hover: light-dark(

src/zen/compact-mode/ZenCompactMode.mjs

@@ -743,6 +743,10 @@ window.gZenCompactModeManager = {
             return;
           }
 
+          if (this._isTabBeingDragged) {
+            return;
+          }
+
           if (this.hoverableElements[i].keepHoverDuration) {
             this.flashElement(
               target,

src/zen/compact-mode/sidebar.inc.css

@@ -12,6 +12,7 @@
   #zen-dragover-background {
     width: calc(100% - var(--zen-toolbox-padding) * 2 - 5px);
     left: unset;
+    transform: translateY(-4px);
   }
 
   #zen-tabbox-wrapper {

src/zen/drag-and-drop/ZenDragAndDrop.js

@@ -39,6 +39,7 @@
       !element ||
       element.closest(".zen-current-workspace-indicator") ||
       element.hasAttribute("split-view-group") ||
+      element.classList.contains("zen-drop-target") ||
       isEssentialsPromo(element)
     ) {
       return element;
@@ -52,6 +53,9 @@
     if (isTabGroupLabel(element)) {
       return element.closest(".tab-group-label-container");
     }
+    if (gBrowser.isTabGroup(element)) {
+      return element.labelContainerElement;
+    }
     throw new Error(`Element "${element.tagName}" is not expected to move`);
   };
 
@@ -101,7 +105,7 @@
 
     startTabDrag(event, tab, ...args) {
       this.ZenDragAndDropService.onDragStart(1);
-
+      gZenCompactModeManager._isTabBeingDragged = true;
       super.startTabDrag(event, tab, ...args);
       const dt = event.dataTransfer;
       if (isTabGroupLabel(tab)) {
@@ -111,11 +115,9 @@
       const { offsetX, offsetY } = this.#getDragImageOffset(event, tab, draggingTabs);
       const dragImage = this.#createDragImageForTabs(draggingTabs);
       this.originalDragImageArgs = [dragImage, offsetX, offsetY];
-      dt.updateDragImage(...this.originalDragImageArgs);
+      dt.setDragImage(...this.originalDragImageArgs);
       if (tab.hasAttribute("zen-essential")) {
-        setTimeout(() => {
+        tab.style.visibility = "hidden";
-          tab.style.visibility = "hidden";
-        }, 0);
       }
     }
 
@@ -125,18 +127,28 @@
       );
       const tabRect = window.windowUtils.getBoundsWithoutFlushing(movingTabs[0]);
       const wrapper = document.createElement("div");
+      let movingTabsCount = Math.min(movingTabs.length, 3);
       wrapper.style.width = tabRect.width + "px";
-      wrapper.style.height = tabRect.height * movingTabs.length + "px";
+      wrapper.style.height = tabRect.height * movingTabsCount + "px";
       wrapper.style.position = "fixed";
       wrapper.style.top = "-9999px";
       periphery.appendChild(wrapper);
-      for (let i = 0; i < movingTabs.length; i++) {
+      for (let i = 0; i < movingTabsCount; i++) {
         const tab = movingTabs[i];
         const tabClone = tab.cloneNode(true);
         if (tab.hasAttribute("zen-essential")) {
           const rect = tab.getBoundingClientRect();
           tabClone.style.minWidth = tabClone.style.maxWidth = `${rect.width}px`;
           tabClone.style.minHeight = tabClone.style.maxHeight = `${rect.height}px`;
+          if (tabClone.hasAttribute("visuallyselected")) {
+            tabClone.style.transform = "translate(-50%, -50%)";
+          }
+        } else if (AppConstants.platform !== "macosx") {
+          // On windows and linux, we still don't add some extra opaqueness
+          // for the tab to be more visible. This is a hacky workaround.
+          // TODO: Make windows and linux DnD use nsZenDragAndDrop::mDragImageOpacity
+          tabClone.style.colorScheme = "light";
+          tabClone.style.color = "black";
         }
         if (i > 0) {
           tabClone.style.transform = `translate(${i * 4}px, -${i * (tabRect.height - 4)}px)`;
@@ -150,6 +162,13 @@
           const label = tabClone.textLabel;
           const tabLabelParentWidth = label.parentElement.getBoundingClientRect().width;
           label.textContent = label.textContent.slice(0, Math.floor(tabLabelParentWidth / 6));
+        } else if (gBrowser.isTabGroup(tabClone) && tabClone.hasAttribute("split-view-group")) {
+          let tabs = tab.tabs;
+          for (let j = 0; j < tabs.length; j++) {
+            const tabInGroup = tabs[j];
+            const tabInGroupClone = tabInGroup.cloneNode(true);
+            tabClone.appendChild(tabInGroupClone);
+          }
         }
       }
       this.#maybeCreateDragImageDot(movingTabs, wrapper);
@@ -197,12 +216,7 @@
         ? dragData.screenY
         : dragData.screenX;
       let allTabs = this._tabbrowserTabs.ariaFocusableItems;
-      let numEssentials = gBrowser._numZenEssentials;
+      let tabs = allTabs;
-      let isEssential = draggedTab.hasAttribute("zen-essential");
-      let tabs = allTabs.slice(
-        isEssential ? 0 : numEssentials,
-        isEssential ? numEssentials : undefined
-      );
       if (!tabs.length) {
         tabs = [...movingTabs];
       }
@@ -235,7 +249,9 @@
       dragData.translateY = translateY;
 
       // Move the dragged tab based on the mouse position.
-      let periphery = document.getElementById("tabbrowser-arrowscrollbox-periphery");
+      let periphery = gZenWorkspaces.activeWorkspaceElement.querySelector(
+        "#tabbrowser-arrowscrollbox-periphery"
+      );
       let lastMovingTab = movingTabs.at(-1);
       let firstMovingTab = movingTabs[0];
       let endEdge = (ele) => ele[screenAxis] + bounds(ele)[size];
@@ -452,9 +468,7 @@
         // 4) we just started dragging and the `oldDropElementIndex` has its default
         //    valuë of `movingTabs[0].elementIndex`. In this case, the drop element
         //    shouldn't be a moving tab, so keep it `undefined`.
-        let lastPossibleDropElement = this._rtlMode
+        let lastPossibleDropElement = this._rtlMode ? tabs.find((t) => t != draggedTab) : undefined;
-          ? tabs.find((t) => t != draggedTab)
-          : tabs.findLast((t) => t != draggedTab);
         let maxElementIndexForDropElement = lastPossibleDropElement?.elementIndex;
         if (Number.isInteger(maxElementIndexForDropElement)) {
           let index = Math.min(oldDropElementIndex, maxElementIndexForDropElement);
@@ -521,7 +535,7 @@
 
       [dropBefore, dropElement] = this.#applyDragoverIndicator(
         event,
-        tabs,
+        dropElement,
         movingTabs,
         draggedTab
       ) ?? [dropBefore, dropElement];
@@ -608,12 +622,30 @@
         if (!this.#changeSpaceTimer) {
           this.#changeSpaceTimer = setTimeout(() => {
             this.clearDragOverVisuals();
-            dt.updateDragImage(...this.originalDragImageArgs);
+            gZenWorkspaces
-            gZenWorkspaces.changeWorkspaceShortcut(
+              .changeWorkspaceShortcut(isNearLeftEdge ? -1 : 1, false, /* Disable wrapping */ true)
-              isNearLeftEdge ? -1 : 1,
+              .then((spaceChanged) => {
-              false,
+                if (AppConstants.platform !== "macosx") {
-              /* Disable wrapping */ true
+                  // See the hack in #createDragImageForTabs for more details which
-            );
+                  // explains why we need to do this on non-macOS platforms.
+                  return;
+                }
+                let tabs = this.originalDragImageArgs[0].children;
+                const { isDarkMode, isExplicitMode } =
+                  gZenThemePicker.getGradientForWorkspace(spaceChanged);
+                for (let tab of tabs) {
+                  if (isExplicitMode) {
+                    tab.style.colorScheme = isDarkMode ? "dark" : "light";
+                  } else {
+                    tab.style.colorScheme = "";
+                  }
+                }
+                requestAnimationFrame(() => {
+                  requestAnimationFrame(() => {
+                    dt.updateDragImage(...this.originalDragImageArgs);
+                  });
+                });
+              });
             this.#changeSpaceTimer = null;
           }, this._dndSwitchSpaceDelay);
         }
@@ -646,6 +678,7 @@
         clientX < 0 || clientX > innerWidth || clientY < 0 || clientY > innerHeight;
       if (isOutOfWindow && !this.#isOutOfWindow) {
         this.#isOutOfWindow = true;
+        gZenViewSplitter.onBrowserDragEndToSplit(event, true);
         this.#maybeClearVerticalPinnedGridDragOver();
         this.clearSpaceSwitchTimer();
         this.clearDragOverVisuals();
@@ -678,25 +711,28 @@
 
     handle_drop(event) {
       this.clearSpaceSwitchTimer();
+      gZenFolders.highlightGroupOnDragOver(null);
       super.handle_drop(event);
       this.#maybeClearVerticalPinnedGridDragOver();
       const dt = event.dataTransfer;
       const activeWorkspace = gZenWorkspaces.activeWorkspace;
       let draggedTab = dt.mozGetDataAt(TAB_DROP_TYPE, 0);
-      if (
+      if (draggedTab.ownerGlobal === window) {
-        isTab(draggedTab) &&
+        if (
-        !draggedTab.hasAttribute("zen-essential") &&
+          isTab(draggedTab) &&
-        draggedTab.getAttribute("zen-workspace-id") != activeWorkspace
+          !draggedTab.hasAttribute("zen-essential") &&
-      ) {
+          draggedTab.getAttribute("zen-workspace-id") != activeWorkspace
-        const movingTabs = draggedTab._dragData?.movingTabs || [draggedTab];
+        ) {
-        for (let tab of movingTabs) {
+          const movingTabs = draggedTab._dragData?.movingTabs || [draggedTab];
-          tab.setAttribute("zen-workspace-id", activeWorkspace);
+          for (let tab of movingTabs) {
+            tab.setAttribute("zen-workspace-id", activeWorkspace);
+          }
+          gBrowser.selectedTab = draggedTab;
+        }
+        if (isTabGroupLabel(draggedTab)) {
+          draggedTab = draggedTab.group;
+          gZenFolders.changeFolderToSpace(draggedTab, activeWorkspace, { hasDndSwitch: true });
         }
-        gBrowser.selectedTab = draggedTab;
-      }
-      if (isTabGroupLabel(draggedTab)) {
-        draggedTab = draggedTab.group;
-        gZenFolders.changeFolderToSpace(draggedTab, activeWorkspace, { hasDndSwitch: true });
       }
       gZenWorkspaces.updateTabsContainers();
     }
@@ -705,7 +741,10 @@
       if (isTabGroupLabel(dropElement)) {
         dropElement = dropElement.group;
       }
-      if (isTabGroupLabel(draggedTab)) {
+      if (
+        isTabGroupLabel(draggedTab) ||
+        (isTab(draggedTab) && draggedTab.group?.hasAttribute("split-view-group"))
+      ) {
         draggedTab = draggedTab.group;
       }
       for (let item of this._tabbrowserTabs.ariaFocusableItems) {
@@ -817,6 +856,9 @@
       if (currentEssenialContainer?.essentialsPromo) {
         currentEssenialContainer.essentialsPromo.remove();
       }
+      // We also call it here to ensure we clear any highlight if the drop happened
+      // outside of a valid drop target.
+      gZenFolders.highlightGroupOnDragOver(null);
       this.ZenDragAndDropService.onDragEnd();
       super.handle_dragend(event);
       this.#removeDragOverBackground();
@@ -833,6 +875,10 @@
         this._tempDragImageParent.remove();
         delete this._tempDragImageParent;
       }
+      delete gZenCompactModeManager._isTabBeingDragged;
+      if (dt.dropEffect !== "move") {
+        gZenCompactModeManager._clearAllHoverStates();
+      }
     }
 
     #applyDragOverBackground(element) {
@@ -872,35 +918,26 @@
     }
 
     // eslint-disable-next-line complexity
-    #applyDragoverIndicator(event, tabs, movingTabs, draggedTab) {
+    #applyDragoverIndicator(event, dropElement, movingTabs, draggedTab) {
       const separation = 4;
-      const dropZoneSelector =
+      const dropZoneSelector = ":is(.zen-drop-target)";
-        ":is(.tabbrowser-tab, .zen-drop-target, .tab-group-label, tab-group[split-view-group])";
       let shouldPlayHapticFeedback = false;
       let showIndicatorUnderNewTabButton = false;
       let dropBefore = false;
-      let dropElement = event.target.closest(dropZoneSelector);
+      let dropElementFromEvent = event.target.closest(dropZoneSelector);
-      if (!dropElement) {
+      dropElement = dropElementFromEvent || dropElement;
-        if (event.target.classList.contains("zen-workspace-empty-space")) {
+      if (!dropElementFromEvent) {
-          dropElement = this._tabbrowserTabs.ariaFocusableItems.at(-1);
+        let hoveringPeriphery = !!event.target.closest("#tabbrowser-arrowscrollbox-periphery");
+        if (event.target.classList.contains("zen-workspace-empty-space") || hoveringPeriphery) {
+          let lastTab = gBrowser.tabs.at(-1);
+          dropElement =
+            (hoveringPeriphery && Services.prefs.getBoolPref("zen.view.show-newtab-button-top")
+              ? this._tabbrowserTabs.ariaFocusableItems.at(
+                  gBrowser._numVisiblePinTabsWithoutCollapsed
+                )
+              : this._tabbrowserTabs.ariaFocusableItems.at(-1)) || lastTab;
           // Only if there are no normal tabs to drop after
-          showIndicatorUnderNewTabButton =
+          showIndicatorUnderNewTabButton = lastTab.hasAttribute("zen-empty-tab");
-            gBrowser.tabs[gBrowser.tabs.length - 1].hasAttribute("zen-empty-tab");
-        } else {
-          const numEssentials = gBrowser._numZenEssentials;
-          const numPinned = gBrowser.pinnedTabCount - numEssentials;
-          const tabToUse =
-            event.target.closest(dropZoneSelector) || draggedTab._dragData?.dropElement;
-          if (!tabToUse) {
-            return null;
-          }
-          const isPinned = tabToUse.pinned;
-          const relativeTabs = tabs.slice(
-            isPinned ? 0 : numPinned,
-            isPinned ? numPinned : undefined
-          );
-          const draggedTabRect = elementToMove(tabToUse).getBoundingClientRect();
-          dropElement = event.clientY > draggedTabRect.top ? relativeTabs.at(-1) : relativeTabs[0];
         }
       }
       dropElement = elementToMove(dropElement);
@@ -909,24 +946,47 @@
         shouldPlayHapticFeedback = this.#lastDropTarget !== null;
         this.#removeDragOverBackground();
       }
-      let isZenFolder = dropElement.parentElement?.isZenFolder;
+      if (!dropElement) {
+        let dragData = draggedTab._dragData;
+        dropElement = dragData.dropElement;
+        dropBefore = dragData.dropBefore;
+      }
+      if (!dropElement) {
+        this.clearDragOverVisuals();
+        return null;
+      }
+      if (dropElement.hasAttribute("zen-empty-tab") && dropElement.group) {
+        let secondTab = dropElement.group.tabs[1];
+        dropElement = secondTab || dropElement.group.labelContainerElement;
+        if (secondTab) {
+          dropBefore = true;
+        }
+      }
+      let possibleFolderElement = dropElement.parentElement;
+      let isZenFolder = possibleFolderElement?.isZenFolder;
       let canHightlightGroup =
-        gZenFolders.highlightGroupOnDragOver(dropElement.parentElement, movingTabs) || !isZenFolder;
+        gZenFolders.highlightGroupOnDragOver(possibleFolderElement, movingTabs) || !isZenFolder;
       let rect = window.windowUtils.getBoundsWithoutFlushing(dropElement);
       const overlapPercent = (event.clientY - rect.top) / rect.height;
       // We wan't to leave a small threshold (20% for example) so we can drag tabs below and above
       // a folder label without dragging into the folder.
       let threshold = Services.prefs.getIntPref("zen.tabs.folder-dragover-threshold-percent") / 100;
       let dropIntoFolder =
-        isZenFolder && (overlapPercent < threshold || overlapPercent > 1 - threshold);
+        isZenFolder &&
+        (overlapPercent < threshold ||
+          (overlapPercent > 1 - threshold &&
+            (possibleFolderElement.collapsed ||
+              possibleFolderElement.childGroupsAndTabs.length < 2)));
       if (
         isTabGroupLabel(draggedTab) &&
         draggedTab.group?.isZenFolder &&
-        (isTab(dropElement) || dropElement.hasAttribute("split-view-group")) &&
+        (((isTab(dropElement) || dropElement.hasAttribute("split-view-group")) &&
-        (!dropElement.pinned || dropElement.hasAttribute("zen-essential"))
+          (!dropElement.pinned || dropElement.hasAttribute("zen-essential"))) ||
+          showIndicatorUnderNewTabButton)
       ) {
+        dropElement = null;
         this.clearDragOverVisuals();
-        return null;
+        return [dropElement, dropBefore];
       }
       if (
         isTab(dropElement) ||
@@ -941,7 +1001,7 @@
         let top = 0;
         threshold =
           Services.prefs.getIntPref("browser.tabs.dragDrop.moveOverThresholdPercent") / 100;
-        if (overlapPercent > threshold) {
+        if (overlapPercent > threshold || showIndicatorUnderNewTabButton) {
           top = Math.round(rect.top + rect.height) + "px";
           dropBefore = false;
         } else {

src/zen/folders/ZenFolders.mjs

@@ -1038,43 +1038,47 @@ class nsZenFolders extends nsZenDOMOperatedFeature {
     const tabFolderWorkingData = new Map();
 
     for (const folderData of data) {
-      const workingData = {
+      try {
-        stateData: folderData,
+        const workingData = {
-        node: null,
+          stateData: folderData,
-        containingTabsFragment: document.createDocumentFragment(),
+          node: null,
-      };
+          containingTabsFragment: document.createDocumentFragment(),
-      tabFolderWorkingData.set(folderData.id, workingData);
+        };
+        tabFolderWorkingData.set(folderData.id, workingData);
 
-      const oldGroup = document.getElementById(folderData.id);
+        const oldGroup = document.getElementById(folderData.id);
-      folderData.emptyTabIds.forEach((id) => {
+        folderData.emptyTabIds.forEach((id) => {
-        oldGroup?.querySelector(`tab[id="${id}"]`)?.setAttribute("zen-empty-tab", true);
+          oldGroup?.querySelector(`tab[id="${id}"]`)?.setAttribute("zen-empty-tab", true);
-      });
+        });
-      if (gBrowser.isTabGroup(oldGroup)) {
+        if (gBrowser.isTabGroup(oldGroup)) {
-        if (!folderData.splitViewGroup) {
+          if (!folderData.splitViewGroup) {
-          const folder = this._createFolderNode({
+            const folder = this._createFolderNode({
-            id: folderData.id,
+              id: folderData.id,
-            label: folderData.name,
+              label: folderData.name,
-            collapsed: folderData.collapsed,
+              collapsed: folderData.collapsed,
-            pinned: folderData.pinned,
+              pinned: folderData.pinned,
-            saveOnWindowClose: folderData.saveOnWindowClose,
+              saveOnWindowClose: folderData.saveOnWindowClose,
-            workspaceId: folderData.workspaceId,
+              workspaceId: folderData.workspaceId,
-          });
+            });
-          folder.setAttribute("id", folderData.id);
+            folder.setAttribute("id", folderData.id);
-          workingData.node = folder;
+            workingData.node = folder;
-          oldGroup.before(folder);
+            oldGroup.before(folder);
-        } else {
+          } else {
-          workingData.node = oldGroup;
+            workingData.node = oldGroup;
-        }
+          }
-        while (oldGroup.tabs.length) {
+          while (oldGroup.tabs.length) {
-          const tab = oldGroup.tabs[0];
+            const tab = oldGroup.tabs[0];
-          if (folderData.workspaceId) {
+            if (folderData.workspaceId) {
-            tab.setAttribute("zen-workspace-id", folderData.workspaceId);
+              tab.setAttribute("zen-workspace-id", folderData.workspaceId);
+            }
+            workingData.containingTabsFragment.appendChild(tab);
+          }
+          if (!folderData.splitViewGroup) {
+            oldGroup.remove();
           }
-          workingData.containingTabsFragment.appendChild(tab);
-        }
-        if (!folderData.splitViewGroup) {
-          oldGroup.remove();
         }
+      } catch (e) {
+        console.error("Error restoring Zen Folders session data:", e);
       }
     }
 
@@ -1134,11 +1138,10 @@ class nsZenFolders extends nsZenDOMOperatedFeature {
    * @param {MozTabbrowserTabGroup|undefined|null} folder The folder to highlight, or null to clear highlight.
    * @param {Array<MozTabbrowserTab>|null} movingTabs The tabs being moved.
    */
-  highlightGroupOnDragOver(folder, movingTabs) {
+  highlightGroupOnDragOver(folder, movingTabs = null) {
     if (folder === this.#lastHighlightedGroup) {
       return true;
     }
-    const tab = movingTabs ? movingTabs[0] : null;
     if (this.#lastHighlightedGroup && this.#lastHighlightedGroup !== folder) {
       if (this.#lastHighlightedGroup.collapsed) {
         this.updateFolderIcon(this.#lastHighlightedGroup, "close");
@@ -1148,7 +1151,6 @@ class nsZenFolders extends nsZenDOMOperatedFeature {
     if (
       folder?.isZenFolder &&
       (!folder.hasAttribute("split-view-group") || !folder.hasAttribute("selected")) &&
-      folder !== tab?.group &&
       !(
         folder.level >= this.#ZEN_MAX_SUBFOLDERS &&
         movingTabs?.some((t) => gBrowser.isTabGroupLabel(t))

src/zen/folders/zen-folders.css

@@ -123,11 +123,11 @@ zen-folder {
         }
 
         &[state="open"] .back {
-          transform: skewX(16deg) translate(-2px, 3.4px) scale(0.85);
+          transform: skewX(16deg) translate(-4px, 2px) scale(0.85);
         }
 
         &[state="open"] :is(.front, .dots, .icon) {
-          transform: skewX(-16deg) translate(11.1px, 3.4px) scale(0.85);
+          transform: skewX(-16deg) translate(8px, 2px) scale(0.85);
         }
 
         & .icon {

src/zen/glance/ZenGlanceManager.mjs

@@ -640,7 +640,6 @@ class nsZenGlanceManager extends nsZenDOMOperatedFeature {
       left: [],
       width: [],
       height: [],
-      transform: [],
     };
 
     const steps = this.#ARC_CONFIG.ARC_STEPS;
@@ -674,7 +673,6 @@ class nsZenGlanceManager extends nsZenDOMOperatedFeature {
       const y =
         startPosition.y + distanceY * eased + arcDirection * arcHeight * (1 - (2 * eased - 1) ** 2);
 
-      sequence.transform.push(`translate(-50%, -50%)`);
       sequence.top.push(`${y}px`);
       sequence.left.push(`${x}px`);
       sequence.width.push(`${currentWidth}px`);

src/zen/kbs/ZenKeyboardShortcuts.mjs

@@ -506,6 +506,10 @@ class KeyShortcut {
     return this.#disabled;
   }
 
+  setDisabled(value) {
+    this.#disabled = value;
+  }
+
   isReserved() {
     return this.#reserved;
   }
@@ -796,6 +800,10 @@ class nsZenKeyboardShortcutsLoader {
         continue;
       }
       let parsed = KeyShortcut.parseFromXHTML(key, { group: "devTools" });
+      // Move "inspector" shortcut to use "L" key instead of "I"
+      if (parsed.getID() == "key_inspector" || parsed.getID() == "key_inspectorMac") {
+        parsed.setNewBinding("L");
+      }
       newShortcutList.push(parsed);
     }
 
@@ -1105,26 +1113,34 @@ class nsZenKeyboardShortcutsVersioner {
 
     if (version < 15) {
       // Migrate from version 13 to 14
-      // Add shortcut to open a new unsynced window: Default accelt+option+N (Ctrl+Alt+N on non-macOS)
+      // Add shortcut to open a new unsynced window: Default accelt+shift+N
       data.push(
         new KeyShortcut(
           "zen-new-unsynced-window",
           "N",
           "",
           ZEN_OTHER_SHORTCUTS_GROUP,
-          AppConstants.platform === "win"
+          nsKeyShortcutModifiers.fromObject({ accel: true, shift: true }),
-            ? nsKeyShortcutModifiers.fromObject({ alt: true })
-            : nsKeyShortcutModifiers.fromObject({ accel: true, alt: true }),
           "cmd_zenNewNavigatorUnsynced",
           "zen-new-unsynced-window-shortcut"
         )
       );
       // Also, change the default for new empty split from + to * on mac
+      // and disable the "Restore closed window" shortcut by default due to conflicts
+      let emptySplitFound = false,
+        undoCloseWindowFound = false;
       for (let shortcut of data) {
         if (shortcut.getID() == "zen-new-empty-split-view" && AppConstants.platform == "macosx") {
           if (shortcut.getKeyName() == "+") {
             shortcut.setNewBinding("*");
           }
+          emptySplitFound = true;
+        } else if (shortcut.getID() == "key_undoCloseWindow") {
+          shortcut.shouldBeEmpty = true;
+          shortcut.setDisabled(true);
+          undoCloseWindowFound = true;
+        }
+        if (emptySplitFound && undoCloseWindowFound) {
           break;
         }
       }

src/zen/sessionstore/ZenSessionManager.sys.mjs

@@ -84,6 +84,7 @@ export class nsZenSessionManager {
       compression: "lz4",
       backupFile,
     });
+    this.log("Session file path:", this.#file.path);
     this.#deferredBackupTask = new lazy.DeferredTask(async () => {
       await this.#createBackupsIfNeeded();
     }, REGENERATION_DEBOUNCE_RATE_MS);
@@ -150,6 +151,19 @@ export class nsZenSessionManager {
         folderIcon: row.getResultByName("folder_icon"),
         isFolderCollapsed: Boolean(row.getResultByName("is_folder_collapsed")),
       }));
+      try {
+        data.recoveryData = await IOUtils.readJSON(
+          PathUtils.join(
+            Services.dirsvc.get("ProfD", Ci.nsIFile).path,
+            "sessionstore-backups",
+            "recovery.jsonlz4"
+          ),
+          { decompress: true }
+        );
+        this.log("Recovered recovery data from sessionstore-backups");
+      } catch {
+        /* ignore errors reading recovery data */
+      }
       this._migrationData = data;
     } catch {
       /* ignore errors during migration */
@@ -165,6 +179,7 @@ export class nsZenSessionManager {
   async readFile() {
     let fileExists = await IOUtils.exists(this.#storeFilePath);
     if (!fileExists) {
+      this.log("Session file does not exist, running migration", this.#storeFilePath);
       this._shouldRunMigration = true;
     }
     this.init();
@@ -181,6 +196,7 @@ export class nsZenSessionManager {
     }
     this.#sidebar = this.#file.data || {};
     if (!this.#sidebar.spaces?.length && !this._shouldRunMigration) {
+      this.log("No spaces data found in session file, running migration", this.#sidebar);
       // If we have no spaces data, we should run migration
       // to restore them from the database. Note we also do a
       // check if we already planned to run migration for optimization.
@@ -189,6 +205,13 @@ export class nsZenSessionManager {
     }
   }
 
+  get #shouldRestoreOnlyPinned() {
+    return (
+      Services.prefs.getIntPref("browser.startup.page", 1) !== BROWSER_STARTUP_RESUME_SESSION ||
+      lazy.PrivateBrowsingUtils.permanentPrivateBrowsing
+    );
+  }
+
   /**
    * Called when the session file is read. Restores the sidebar data
    * into all windows.
@@ -197,15 +220,22 @@ export class nsZenSessionManager {
    *        The initial session state read from the session file.
    */
   onFileRead(initialState) {
-    if (!lazy.gWindowSyncEnabled) {
-      return initialState;
-    }
     // For the first time after migration, we restore the tabs
     // That where going to be restored by SessionStore. The sidebar
     // object will always be empty after migration because we haven't
     // gotten the opportunity to save the session yet.
     if (this._shouldRunMigration) {
-      this.#runStateMigration(initialState);
+      initialState = this.#runStateMigration(initialState);
+    }
+    if (!lazy.gWindowSyncEnabled) {
+      if (initialState?.windows?.length && this.#shouldRestoreOnlyPinned) {
+        this.log("Window sync disabled, restoring only pinned tabs");
+        for (let i = 0; i < initialState.windows.length; i++) {
+          let winData = initialState.windows[i];
+          winData.tabs = (winData.tabs || []).filter((tab) => tab.pinned);
+        }
+      }
+      return initialState;
     }
     // If there are no windows, we create an empty one. By default,
     // firefox would create simply a new empty window, but we want
@@ -215,14 +245,15 @@ export class nsZenSessionManager {
     if (!initialState?.windows?.length) {
       this.log("No windows found in initial state, creating an empty one");
       initialState ||= {};
-      initialState.windows = this._shouldRunMigration ? [] : [{}];
+      initialState.windows = [
+        {
+          tabs: [],
+        },
+      ];
     }
     // When we don't have browser.startup.page set to resume session,
     // we only want to restore the pinned tabs into the new windows.
-    const shouldRestoreOnlyPinned =
+    if (this.#shouldRestoreOnlyPinned && this.#sidebar?.tabs) {
-      Services.prefs.getIntPref("browser.startup.page", 1) !== BROWSER_STARTUP_RESUME_SESSION ||
-      lazy.PrivateBrowsingUtils.permanentPrivateBrowsing;
-    if (shouldRestoreOnlyPinned && this.#sidebar?.tabs) {
       this.log("Restoring only pinned tabs into windows");
       const sidebar = this.#sidebar;
       sidebar.tabs = (sidebar.tabs || []).filter((tab) => tab.pinned);
@@ -249,9 +280,9 @@ export class nsZenSessionManager {
         }
         this.#restoreWindowData(winData);
       }
-    } else {
+    } else if (initialState) {
       this.log("Saving windata state after migration");
-      this.saveState(initialState);
+      this.saveState(Cu.cloneInto(initialState, {}));
     }
     delete this._shouldRunMigration;
     return initialState;
@@ -272,8 +303,19 @@ export class nsZenSessionManager {
    * @param {object} initialState
    *        The initial session state read from the session file.
    */
+  // eslint-disable-next-line complexity
   #runStateMigration(initialState) {
-    this.log("Restoring tabs from Places DB after migration", initialState, this._migrationData);
+    this.log(
+      "Restoring tabs from Places DB after migration",
+      initialState,
+      initialState?.lastSessionState,
+      this._migrationData
+    );
+    if (!initialState?.windows?.length && this._migrationData?.recoveryData) {
+      this.log("Using recovery data for migration");
+      initialState = this._migrationData.recoveryData;
+    }
+    delete this._migrationData?.recoveryData;
     // Restore spaces into the sidebar object if we don't
     // have any yet.
     if (!this.#sidebar.spaces?.length) {
@@ -282,6 +324,12 @@ export class nsZenSessionManager {
         spaces: this._migrationData?.spaces || [],
       };
     }
+    if (
+      !initialState?.windows?.length &&
+      (initialState?.lastSessionState || initialState?.deferredInitialState)
+    ) {
+      initialState = { ...(initialState.lastSessionState || initialState.deferredInitialState) };
+    }
     // There might be cases where there are no windows in the
     // initial state, for example if the user had 'restore previous
     // session' disabled before migration. In that case, we try
@@ -295,6 +343,14 @@ export class nsZenSessionManager {
         this.log("Restoring tabs from last closed normal window");
       }
     }
+    if (!initialState?.windows?.length) {
+      initialState ||= {};
+      initialState.windows = [
+        {
+          tabs: [],
+        },
+      ];
+    }
     for (const winData of initialState?.windows || []) {
       winData.spaces = this._migrationData?.spaces || [];
       if (winData.tabs) {
@@ -309,9 +365,17 @@ export class nsZenSessionManager {
         }
       }
     }
-    // Save the state to the sidebar object so that it gets written
+    return initialState;
-    // to the session file.
+  }
-    delete this._migrationData;
+
+  /**
+   * Determines if a given window data object is saveable.
+   *
+   * @param {object} aWinData - The window data object to check.
+   * @returns {boolean} True if the window is saveable, false otherwise.
+   */
+  #isWindowSaveable(aWinData) {
+    return !aWinData.isPopup && !aWinData.isTaskbarTab && !aWinData.isZenUnsynced;
   }
 
   /**
@@ -321,8 +385,8 @@ export class nsZenSessionManager {
    */
   saveState(state) {
     let windows = state?.windows || [];
-    windows = windows.filter((win) => !win.isPopup && !win.isTaskbarTab && !win.isZenUnsynced);
+    windows = windows.filter((win) => this.#isWindowSaveable(win));
-    if (!windows.length || !lazy.gWindowSyncEnabled) {
+    if (!windows.length) {
       // Don't save (or even collect) anything in permanent private
       // browsing mode. We also don't want to save if there are no windows.
       return;
@@ -502,7 +566,7 @@ export class nsZenSessionManager {
    *        Whether this new window is being restored from a closed window.
    */
   restoreNewWindow(aWindow, SessionStoreInternal, fromClosedWindow = false) {
-    if (aWindow.gZenWorkspaces?.privateWindowOrDisabled || !lazy.gWindowSyncEnabled) {
+    if (aWindow.gZenWorkspaces?.privateWindowOrDisabled) {
       return;
     }
     this.log("Restoring new window with Zen session data");
@@ -520,6 +584,10 @@ export class nsZenSessionManager {
       this.#restoreWindowData(newWindow);
     }
     newWindow.tabs = this.#filterUnusedTabs(newWindow.tabs || []);
+    if (!lazy.gWindowSyncEnabled) {
+      // Don't bring over any unpinned tabs if window sync is disabled.
+      newWindow.tabs = newWindow.tabs.filter((tab) => tab.pinned);
+    }
 
     // These are window-specific from the previous window state that
     // we don't want to restore into the new window. Otherwise, new

src/zen/sessionstore/ZenWindowSync.sys.mjs

@@ -10,17 +10,17 @@ const lazy = {};
 
 ChromeUtils.defineESModuleGetters(lazy, {
   BrowserWindowTracker: "resource:///modules/BrowserWindowTracker.sys.mjs",
-  SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
   TabStateFlusher: "resource:///modules/sessionstore/TabStateFlusher.sys.mjs",
   // eslint-disable-next-line mozilla/valid-lazy
   ZenSessionStore: "resource:///modules/zen/ZenSessionManager.sys.mjs",
   TabStateCache: "resource:///modules/sessionstore/TabStateCache.sys.mjs",
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
 });
 
-XPCOMUtils.defineLazyPreferenceGetter(lazy, "gWindowSyncEnabled", "zen.window-sync.enabled");
+XPCOMUtils.defineLazyPreferenceGetter(lazy, "gWindowSyncEnabled", "zen.window-sync.enabled", true);
 XPCOMUtils.defineLazyPreferenceGetter(lazy, "gShouldLog", "zen.window-sync.log", true);
 
-const OBSERVING = ["browser-window-before-show"];
+const OBSERVING = ["browser-window-before-show", "sessionstore-windows-restored"];
 const INSTANT_EVENTS = ["SSWindowClosing"];
 const UNSYNCED_WINDOW_EVENTS = ["TabOpen"];
 const EVENTS = [
@@ -140,16 +140,13 @@ class nsZenWindowSync {
   }
 
   init() {
-    if (!lazy.gWindowSyncEnabled || this.#initialized) {
+    if (this.#initialized) {
       return;
     }
     this.#initialized = true;
     for (let topic of OBSERVING) {
       Services.obs.addObserver(this, topic);
     }
-    lazy.SessionStore.promiseAllWindowsRestored.then(() => {
-      this.#onSessionStoreInitialized();
-    });
   }
 
   uninit() {
@@ -176,6 +173,13 @@ class nsZenWindowSync {
    * @param {Window} aWindow - The browser window that is about to be shown.
    */
   #onWindowBeforeShow(aWindow) {
+    if (
+      aWindow.gZenWindowSync ||
+      aWindow.document.documentElement.hasAttribute("zen-unsynced-window")
+    ) {
+      return;
+    }
+    this.log("Setting up window sync for window", aWindow);
     // There are 2 possibilities to know if we are trying to open
     // a new *unsynced* window:
     // 1. We are passing `zen-unsynced` in the window arguments.
@@ -221,6 +225,7 @@ class nsZenWindowSync {
     // that didn't have this feature.
     await this.#runOnAllWindowsAsync(null, async (aWindow) => {
       const { gZenWorkspaces } = aWindow;
+      this.#onWindowBeforeShow(aWindow);
       await gZenWorkspaces.promiseInitialized;
       for (let tab of gZenWorkspaces.allStoredTabs) {
         if (!tab.id) {
@@ -288,6 +293,10 @@ class nsZenWindowSync {
         this.#onWindowBeforeShow(aSubject);
         break;
       }
+      case "sessionstore-windows-restored": {
+        this.#onSessionStoreInitialized();
+        break;
+      }
     }
   }
 
@@ -300,6 +309,9 @@ class nsZenWindowSync {
     ) {
       return;
     }
+    if (!lazy.gWindowSyncEnabled && !UNSYNCED_WINDOW_EVENTS.includes(aEvent.type)) {
+      return;
+    }
     if (INSTANT_EVENTS.includes(aEvent.type)) {
       this.#handleNextEvent(aEvent);
       return;
@@ -505,7 +517,11 @@ class nsZenWindowSync {
    */
   #moveItemToMatchOriginal(aOriginalItem, aTargetItem, aWindow, { isEssential, isPinned }) {
     const { gBrowser, gZenWorkspaces } = aWindow;
-    const originalSibling = aOriginalItem.previousElementSibling;
+    let originalSibling = aOriginalItem.previousElementSibling;
+    if (originalSibling?.classList.contains("space-fake-collapsible-start")) {
+      // Skip space fake elements.
+      originalSibling = originalSibling.previousElementSibling;
+    }
     let isFirstTab = true;
     if (gBrowser.isTabGroup(originalSibling) || gBrowser.isTab(originalSibling)) {
       isFirstTab =
@@ -577,7 +593,17 @@ class nsZenWindowSync {
    * @param {object} aOtherTab - The tab in the other window.
    */
   async #swapBrowserDocShellsAsync(aOurTab, aOtherTab) {
-    let promise = this.#maybeFlushTabState(aOurTab);
+    if (!this.#canSwapBrowsers(aOurTab, aOtherTab)) {
+      this.log(
+        `Cannot swap browsers between tabs ${aOurTab.id} and ${aOtherTab.id} due to process mismatch`
+      );
+      return;
+    }
+    if (aOtherTab.closing) {
+      this.log(`Cannot swap browsers, other tab ${aOtherTab.id} is closing`);
+      return;
+    }
+    let promise = this.#maybeFlushTabState(aOtherTab);
     await this.#styleSwapedBrowsers(
       aOurTab,
       aOtherTab,
@@ -626,6 +652,27 @@ class nsZenWindowSync {
     }
   }
 
+  /**
+   * Checks if two tabs can have their browsers swapped.
+   *
+   * @param {object} aOurTab - The tab in the current window.
+   * @param {object} aOtherTab - The tab in the other window.
+   * @returns {boolean} True if the tabs can be swapped, false otherwise.
+   */
+  #canSwapBrowsers(aOurTab, aOtherTab) {
+    // In this case, the other tab is most likely discarded or pending.
+    // We *shouldn't* care about this scenario since the remoteness should be
+    // the same anyways.
+    if (!aOurTab.linkedBrowser || !aOtherTab.linkedBrowser) {
+      return true;
+    }
+    // Can't swap between chrome and content processes.
+    if (aOurTab.linkedBrowser.isRemoteBrowser != aOtherTab.linkedBrowser.isRemoteBrowser) {
+      return false;
+    }
+    return true;
+  }
+
   /**
    * Swaps the browser docshells between two tabs.
    *
@@ -638,19 +685,32 @@ class nsZenWindowSync {
    */
   #swapBrowserDocShellsInner(aOurTab, aOtherTab, { focus = true, onClose = false } = {}) {
     // Can't swap between chrome and content processes.
-    if (aOurTab.linkedBrowser.isRemoteBrowser != aOtherTab.linkedBrowser.isRemoteBrowser) {
+    if (!this.#canSwapBrowsers(aOurTab, aOtherTab)) {
+      this.log(
+        `Cannot swap browsers between tabs ${aOurTab.id} and ${aOtherTab.id} due to process mismatch`
+      );
       return null;
     }
     // See https://github.com/zen-browser/desktop/issues/11851, swapping the browsers
     // don't seem to update the state's cache properly, leading to issues when restoring
     // the session later on.
-    let tabStateEntries = this.#getTabEntriesFromCache(aOurTab);
+    let tabStateEntries = this.#getTabEntriesFromCache(aOtherTab);
+    const setStateToTab = () => {
+      if (!tabStateEntries?.entries.length) {
+        this.log(`Error: No tab state entries found for tab ${aOurTab.id} during swap`);
+        return;
+      }
+      lazy.TabStateCache.update(aOurTab.linkedBrowser.permanentKey, {
+        history: tabStateEntries,
+      });
+    };
     // Running `swapBrowsersAndCloseOther` doesn't expect us to use the tab after
     // the operation, so it doesn't really care about cleaning up the other tab.
     // We need to make a new tab progress listener for the other tab after the swap.
     this.#withRestoreTabProgressListener(
       aOtherTab,
       () => {
+        setStateToTab();
         this.log(`Swapping docshells between windows for tab ${aOurTab.id}`);
         aOurTab.ownerGlobal.gBrowser.swapBrowsersAndCloseOther(aOurTab, aOtherTab, false);
         // Since we are moving progress listeners around, there's a chance that we
@@ -701,13 +761,7 @@ class nsZenWindowSync {
     // we would start receiving invalid history changes from the the incorrect
     // browser view that was just swapped out.
     return this.#maybeFlushTabState(aOurTab).finally(() => {
-      if (!tabStateEntries?.entries.length) {
+      setStateToTab();
-        this.log(`Error: No tab state entries found for tab ${aOtherTab.id} during swap`);
-        return;
-      }
-      lazy.TabStateCache.update(aOurTab.linkedBrowser.permanentKey, {
-        history: tabStateEntries,
-      });
     });
   }
 
@@ -905,7 +959,7 @@ class nsZenWindowSync {
     if (aTab.linkedBrowser) {
       cachedState = lazy.TabStateCache.get(aTab.linkedBrowser.permanentKey);
     }
-    return cachedState?.history?.entries ? cachedState.history : { entries: [] };
+    return cachedState?.history?.entries ? Cu.cloneInto(cachedState.history, {}) : { entries: [] };
   }
 
   /**
@@ -1007,20 +1061,37 @@ class nsZenWindowSync {
     moveAllTabsToWindow(true);
   }
 
+  /**
+   * Updates the initial pinned tab image for all windows if not already set.
+   *
+   * @param {object} aTab - The tab to update the image for.
+   */
+  #maybeEditAllTabsEntryImage(aTab) {
+    if (!aTab?._zenPinnedInitialState || aTab._zenPinnedInitialState.image) {
+      return;
+    }
+    let image = aTab.getAttribute("image") || aTab.ownerGlobal.gBrowser.getIcon(aTab);
+    this.#runOnAllWindows(null, (win) => {
+      const targetTab = this.getItemFromWindow(win, aTab.id);
+      if (targetTab) {
+        targetTab._zenPinnedInitialState.image = image;
+      }
+    });
+  }
+
   /* Mark: Event Handlers */
 
   on_TabOpen(aEvent) {
     const tab = aEvent.target;
     const window = tab.ownerGlobal;
     const isUnsyncedWindow = window.gZenWorkspaces.privateWindowOrDisabled;
-
     if (tab.id) {
       // This tab was opened as part of a sync operation.
       return;
     }
     tab._zenContentsVisible = true;
     tab.id = this.#newTabSyncId;
-    if (isUnsyncedWindow) {
+    if (isUnsyncedWindow || !lazy.gWindowSyncEnabled) {
       return;
     }
     this.#runOnAllWindows(window, (win) => {
@@ -1045,6 +1116,7 @@ class nsZenWindowSync {
       // No need to sync icon changes for tabs that aren't active in this window.
       return;
     }
+    this.#maybeEditAllTabsEntryImage(aEvent.target);
     return this.#delegateGenericSyncEvent(aEvent, SYNC_FLAG_ICON);
   }
 
@@ -1103,6 +1175,9 @@ class nsZenWindowSync {
   }
 
   on_focus(aEvent) {
+    if (typeof aEvent.target !== "object") {
+      return;
+    }
     const { ownerGlobal: window } = aEvent.target;
     if (
       !window?.gBrowser ||
@@ -1258,7 +1333,11 @@ class nsZenWindowSync {
       }
     });
 
-    return this.#onTabSwitchOrWindowFocus(window, null, /* ignoreSameTab = */ true);
+    return new Promise((resolve) => {
+      lazy.setTimeout(() => {
+        this.#onTabSwitchOrWindowFocus(window, null, /* ignoreSameTab = */ true).finally(resolve);
+      }, 0);
+    });
   }
 }
 

src/zen/split-view/ZenViewSplitter.mjs

@@ -1354,10 +1354,15 @@ class nsZenViewSplitter extends nsZenDOMOperatedFeature {
       }
     });
 
+    // Apply grid to tabs first to set zen-split attribute on containers
+    // before setting zen-split-view on parents. This prevents the black flash
+    // caused by CSS rules that hide containers without zen-split attribute
+    // when the parent has zen-split-view attribute.
+    this.applyGridToTabs(splitData.tabs);
+
     this.tabBrowserPanel.setAttribute("zen-split-view", "true");
     document.getElementById("tabbrowser-tabbox").setAttribute("zen-split-view", "true");
 
-    this.applyGridToTabs(splitData.tabs);
     this.applyGridLayout(splitData.layoutTree);
     this.setTabsDocShellState(splitData.tabs, true);
     this.toggleWrapperDisplay(true);
@@ -1403,6 +1408,10 @@ class nsZenViewSplitter extends nsZenDOMOperatedFeature {
       tab.setAttribute("split-view", "true");
       const container = tab.linkedBrowser?.closest(".browserSidebarContainer");
       container.setAttribute("is-zen-split", "true");
+      // Set zen-split early to prevent visibility flash when switching workspaces.
+      // The CSS rule for [is-zen-split]:not([zen-split]) sets visibility:hidden,
+      // so we must set zen-split before the parent zen-split-view attribute is applied.
+      container.setAttribute("zen-split", "true");
       if (!container?.querySelector(".zen-tab-rearrange-button")) {
         // insert a header into the container
         const header = this._createHeader(container);
@@ -2084,45 +2093,53 @@ class nsZenViewSplitter extends nsZenDOMOperatedFeature {
     this._sessionRestoring = true;
 
     for (const groupData of data) {
-      const group = document.getElementById(groupData.groupId);
+      try {
-      if (!gBrowser.isTabGroup(group)) {
+        const group = document.getElementById(groupData.groupId);
-        continue;
+        if (!gBrowser.isTabGroup(group)) {
-      }
+          continue;
-
-      // Backwards compatibility
-      group.setAttribute("split-view-group", "true");
-      if (!groupData?.layoutTree) {
-        this.splitTabs(group.tabs, group.gridType);
-        delete this._sessionRestoring;
-        return;
-      }
-
-      const deserializeNode = (nodeData) => {
-        if (nodeData.type === "leaf") {
-          const tab = document.getElementById(nodeData.tabId);
-          if (!tab) {
-            return null;
-          }
-          return new nsSplitLeafNode(tab, nodeData.sizeInParent);
         }
 
-        const splitter = new nsSplitNode(nodeData.direction, nodeData.sizeInParent);
+        // Backwards compatibility
-        splitter._children = [];
+        group.setAttribute("split-view-group", "true");
-
+        if (!groupData?.layoutTree) {
-        for (const childData of nodeData.children) {
+          this.splitTabs(group.tabs, group.gridType);
-          const childNode = deserializeNode(childData);
+          delete this._sessionRestoring;
-          if (childNode) {
+          return;
-            childNode.parent = splitter;
-            splitter._children.push(childNode);
-          }
         }
 
-        return splitter;
+        const deserializeNode = (nodeData) => {
-      };
+          if (nodeData.type === "leaf") {
+            const tab = document.getElementById(nodeData.tabId);
+            if (!tab) {
+              return null;
+            }
+            return new nsSplitLeafNode(tab, nodeData.sizeInParent);
+          }
 
-      const layout = deserializeNode(groupData.layoutTree);
+          const splitter = new nsSplitNode(nodeData.direction, nodeData.sizeInParent);
-      const splitData = this.splitTabs(group.tabs, groupData.gridType, -1);
+          splitter._children = [];
-      splitData.layoutTree = layout;
+
+          for (const childData of nodeData.children) {
+            const childNode = deserializeNode(childData);
+            if (childNode) {
+              childNode.parent = splitter;
+              splitter._children.push(childNode);
+            }
+          }
+
+          return splitter;
+        };
+
+        const layout = deserializeNode(groupData.layoutTree);
+        const splitData = this.splitTabs(group.tabs, groupData.gridType, -1);
+        if (splitData) {
+          splitData.layoutTree = layout;
+        } else {
+          gBrowser.removeTabGroup(group);
+        }
+      } catch (e) {
+        console.error("Error restoring split view session data:", e);
+      }
     }
 
     delete this._sessionRestoring;

src/zen/tabs/ZenPinnedTabManager.mjs

@@ -76,6 +76,17 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
     this._zenClickEventListener = this._onTabClick.bind(this);
 
     gZenWorkspaces._resolvePinnedInitialized();
+    if (lazy.zenPinnedTabRestorePinnedTabsToPinnedUrl) {
+      gZenWorkspaces.promiseInitialized.then(() => {
+        for (const tab of gZenWorkspaces.allStoredTabs) {
+          try {
+            this.resetPinnedTab(tab);
+          } catch (ex) {
+            console.error("Error restoring pinned tab:", ex);
+          }
+        }
+      });
+    }
   }
 
   log(message) {
@@ -162,7 +173,7 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
     this._resetTabToStoredState(tab);
   }
 
-  async replacePinnedUrlWithCurrent(tab = undefined) {
+  replacePinnedUrlWithCurrent(tab = undefined) {
     tab ??= TabContextMenu.contextTab;
     if (!tab || !tab.pinned) {
       return;
@@ -560,6 +571,16 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
       );
       const essentialTabsTarget = event.target.closest(".zen-essentials-container");
       const tabsTarget = !pinnedTabsTarget;
+      let currentEssenialContainer = gZenWorkspaces.getCurrentEssentialsContainer();
+      if (currentEssenialContainer?.essentialsPromo) {
+        currentEssenialContainer.essentialsPromo.remove();
+      }
+
+      movingTabs = movingTabs.filter((tab) =>
+        gBrowser.isTabGroupLabel(tab) && tab.group?.isZenFolder
+          ? !tabsTarget && !essentialTabsTarget
+          : true
+      );
 
       // TODO: Solve the issue of adding a tab between two groups
       // Remove group labels from the moving tabs and replace it
@@ -582,7 +603,10 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
         let isRegularTabs = false;
         // Check for essentials container
         if (essentialTabsTarget) {
-          if (!draggedTab.hasAttribute("zen-essential") && !draggedTab?.group) {
+          if (
+            !draggedTab.hasAttribute("zen-essential") &&
+            !draggedTab?.group?.hasAttribute("split-view-group")
+          ) {
             moved = true;
             isVertical = false;
             hasActuallyMoved = this.addToEssentials(draggedTab);
@@ -651,7 +675,6 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
           }
         }
       }
-
       return moved;
     } catch (ex) {
       console.error("Error moving tabs:", ex);

src/zen/tabs/zen-tabs/vertical-tabs.css

@@ -296,7 +296,7 @@
   border-bottom: 0px solid transparent !important;
 
   --tab-block-margin: 2px;
-  --tab-selected-bgcolor: light-dark(rgba(255, 255, 255, 0.8), rgba(255, 255, 255, 0.12));
+  --tab-selected-bgcolor: light-dark(rgba(255, 255, 255, 0.8), rgba(255, 255, 255, 0.18));
   --tab-selected-shadow: 0 1px 1px 1px light-dark(rgba(0, 0, 0, 0.09), rgba(0, 0, 0, 0.05)) !important;
   grid-gap: 0 !important;
 
@@ -496,6 +496,11 @@
     padding-left: 0 !important;
   }
 
+  #tabbrowser-tabs {
+    --toolbarbutton-inner-padding: 10px !important;
+    --tab-icon-end-margin: var(--toolbarbutton-inner-padding) !important;
+  }
+
   & .tab-audio-button {
     margin-inline-start: -4px;
     margin-inline-end: 2px;
@@ -665,7 +670,7 @@
       .tab-sharing-icon-overlay,
       .tab-icon-overlay {
         margin-inline-end: var(--toolbarbutton-inner-padding) !important;
-        margin-inline-start: calc(var(--toolbarbutton-inner-padding) / 4) !important;
+        margin-inline-start: calc(var(--toolbarbutton-inner-padding) / 3) !important;
       }
     }
   }
@@ -929,7 +934,7 @@
   height: calc(100% - var(--tab-block-margin) * 2);
   margin-left: calc(-1 * var(--tab-inline-padding) + var(--tab-block-margin));
   margin-right: 8px;
-  padding: 0 calc(var(--toolbarbutton-inner-padding) - 2px) 0 calc(var(--toolbarbutton-inner-padding) / 4 + var(--tab-inline-padding) - 2px);
+  padding: 0 calc(var(--toolbarbutton-inner-padding) - 2px) 0 calc(var(--toolbarbutton-inner-padding) / 3 + var(--tab-inline-padding) - 2px);
   border-radius: 0;
   border-top-left-radius: var(--border-radius-medium);
   width: unset;

src/zen/tests/mochitests/sandbox/browser_content_sandbox_fs_tests.js

@@ -682,6 +682,13 @@ async function testFileAccessWindowsOnly() {
   let tests = [];
 
   let extDir = GetPerUserExtensionDir();
+  // We used to unconditionally create this directory from Firefox, but that
+  // was dropped in bug 2001887. The value of this directory is questionable;
+  // the test was added in Firefox 56 (bug 1403744) to cover legacy add-ons,
+  // but legacy add-on support was discontinued in Firefox 57, and we stopped
+  // sideloading add-ons from this directory on all builds except ESR in
+  // Firefox 74 (bug 1602840).
+  await IOUtils.makeDirectory(extDir.path);
   tests.push({
     desc: "per-user extensions dir",
     ok: true,

src/zen/tests/mochitests/sandbox/browser_content_sandbox_fs_xdg_xdgConfigHome.js

@@ -22,6 +22,13 @@ add_setup(async function setup() {
   const xdgConfigHome = Services.env.get("XDG_CONFIG_HOME");
   Assert.greater(xdgConfigHome.length, 1, "XDG_CONFIG_HOME is defined");
 
+  // Verify the profile directory is inside XDG_CONFIG_HOME
+  const profileDir = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  Assert.ok(
+    profileDir.path.startsWith(xdgConfigHome),
+    `Profile directory (${profileDir.path}) should be inside XDG_CONFIG_HOME (${xdgConfigHome})`
+  );
+
   // If it is there, do actual testing
   sanityChecks();
 });

src/zen/tests/mochitests/sandbox/browser_xdg_default.toml

@@ -12,11 +12,14 @@ support-files = [
   "browser_content_sandbox_utils.js",
   "browser_content_sandbox_fs_tests.js",
 ]
-# .config needs to exists for the sandbox to properly add it
+test-directories = [
-test-directories = ["/tmp/.xdg_default_test", "/tmp/.xdg_default_test/.config"]
+  "/tmp/.xdg_default_test",
+  "/tmp/.xdg_default_test/.config/mozilla/firefox/xdg_default_profile",
+]
 environment = [
   "HOME=/tmp/.xdg_default_test",
 ]
+profile-path = "/tmp/.xdg_default_test/.config/mozilla/firefox/xdg_default_profile"
 
 ["browser_content_sandbox_fs_xdg_default.js"]
 run-if = ["os == 'linux'"]

src/zen/tests/mochitests/sandbox/browser_xdg_mozLegacyHome.toml

@@ -12,12 +12,17 @@ support-files = [
   "browser_content_sandbox_utils.js",
   "browser_content_sandbox_fs_tests.js",
 ]
-test-directories = ["/tmp/.xdg_mozLegacyHome_test/.config", "/tmp/.xdg_config_home_test"]
+test-directories = [
+  "/tmp/.xdg_mozLegacyHome_test/.config",
+  "/tmp/.xdg_config_home_test",
+  "/tmp/.xdg_mozLegacyHome_test/.mozilla/firefox/xdg_mozLegacyHome_profile",
+]
 environment = [
   "XDG_CONFIG_HOME=/tmp/.xdg_config_home_test",
   "HOME=/tmp/.xdg_mozLegacyHome_test",
   "MOZ_LEGACY_HOME=1",
 ]
+profile-path = "/tmp/.xdg_mozLegacyHome_test/.mozilla/firefox/xdg_mozLegacyHome_profile"
 
 ["browser_content_sandbox_fs_xdg_mozLegacyHome.js"]
 run-if = ["os == 'linux'"]

src/zen/tests/mochitests/sandbox/browser_xdg_xdgConfigHome.toml

@@ -11,11 +11,15 @@ support-files = [
   "browser_content_sandbox_utils.js",
   "browser_content_sandbox_fs_tests.js",
 ]
-test-directories = "/tmp/.xdg_config_home_test"
+test-directories = [
+  "/tmp/.xdg_config_home_test",
+  "/tmp/.xdg_config_home_test/mozilla/firefox/xdg_config_home_profile",
+]
 environment = [
   "XDG_CONFIG_HOME=/tmp/.xdg_config_home_test",
   "MOZ_LEGACY_HOME=0",
 ]
+profile-path = "/tmp/.xdg_config_home_test/mozilla/firefox/xdg_config_home_profile"
 
 ["browser_content_sandbox_fs_xdg_xdgConfigHome.js"]
 run-if = [

src/zen/workspaces/ZenGradientGenerator.mjs

@@ -1348,7 +1348,8 @@ export class nsZenThemePicker extends nsZenMultiWindowFeature {
   }
 
   getToolbarColor(isDarkMode = false) {
-    return isDarkMode ? [255, 255, 255, 0.6] : [0, 0, 0, 0.6]; // Default toolbar
+    const opacity = 0.8;
+    return isDarkMode ? [255, 255, 255, opacity] : [0, 0, 0, opacity]; // Default toolbar
   }
 
   onWorkspaceChange(workspace, skipUpdate = false, theme = null) {

src/zen/workspaces/ZenWorkspaces.mjs

@@ -6,6 +6,12 @@
 
 import { nsZenThemePicker } from "chrome://browser/content/zen-components/ZenGradientGenerator.mjs";
 
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  ZenSessionStore: "resource:///modules/zen/ZenSessionManager.sys.mjs",
+});
+
 /**
  * Zen Spaces manager. This class is mainly responsible for the UI
  * and user interactions but it also contains some logic to manage
@@ -801,7 +807,7 @@ class nsZenWorkspaces {
         chromeFlags & Ci.nsIWebBrowserChrome.CHROME_MENUBAR;
       return this._shouldHaveWorkspaces;
     }
-    return this._shouldHaveWorkspaces;
+    return this._shouldHaveWorkspaces && !document.documentElement.hasAttribute("taskbartab");
   }
 
   get isPrivateWindow() {
@@ -888,6 +894,13 @@ class nsZenWorkspaces {
       return Promise.resolve();
     }
     const spacesFromStore = aWinData.spaces || [];
+    if (
+      !this.privateWindowOrDisabled &&
+      spacesFromStore.length === 0 &&
+      lazy.ZenSessionStore._migrationData
+    ) {
+      spacesFromStore.push(...lazy.ZenSessionStore._migrationData.spaces);
+    }
     this._workspaceCache = spacesFromStore.length
       ? [...spacesFromStore]
       : [this.#createWorkspaceData("Space", undefined)];
@@ -1031,11 +1044,17 @@ class nsZenWorkspaces {
       delete this._initialTab;
     }
 
-    if (gZenVerticalTabsManager._canReplaceNewTab && showed) {
+    // Wait for the next event loop to ensure that the startup focus logic by
-      BrowserCommands.openTab();
+    // firefox has finished doing it's thing.
-    } else if (!showed) {
+    setTimeout(() => {
-      gBrowser.selectedBrowser.focus();
+      setTimeout(() => {
-    }
+        if (gZenVerticalTabsManager._canReplaceNewTab && showed) {
+          BrowserCommands.openTab();
+        } else if (!showed) {
+          gBrowser.selectedBrowser.focus();
+        }
+      });
+    });
 
     if (
       !gZenVerticalTabsManager._canReplaceNewTab &&
@@ -2739,6 +2758,7 @@ class nsZenWorkspaces {
 
     let nextWorkspace = workspaces[targetIndex];
     await this.changeWorkspace(nextWorkspace, { whileScrolling });
+    return nextWorkspace;
   }
 
   #initializeWorkspaceTabContextMenus() {

src/zen/workspaces/zen-workspaces.css

@@ -155,7 +155,7 @@
 
 /* Mark workspaces indicator */
 .zen-current-workspace-indicator {
-  --indicator-gap: 10px;
+  --indicator-gap: calc(var(--toolbarbutton-inner-padding) - 1px);
   padding: calc(2px + var(--tab-inline-padding) + var(--zen-toolbox-padding));
   font-weight: 500;
   position: relative;
@@ -208,8 +208,14 @@
     align-items: center;
     fill-opacity: 0.6;
     -moz-context-properties: fill-opacity, fill;
-    fill: currentColor;
+    fill: var(--toolbox-textcolor);
-    font-size: 14px;
+    font-size: 16px;
+    padding-top: 2px;
+    color: light-dark(rgba(0, 0, 0, 0.8), rgba(255, 255, 255, 0.8));
+
+    & img {
+      transform: translateY(-1px);
+    }
 
     &[zen-emoji-open='true']::before {
       border: 1px dashed light-dark(rgba(0, 0, 0, .5), rgba(255, 255, 255, .5));
@@ -225,19 +231,19 @@
 
     @media (-moz-platform: windows) {
       & img {
-        margin-bottom: -4px;
+        margin-bottom: -2px;
       }
     }
   }
 
   .zen-current-workspace-indicator-name {
-    display: flex;
+    display: block;
     white-space: nowrap;
     overflow: hidden;
     text-overflow: ellipsis;
     cursor: auto;
+    white-space: nowrap;
     font-weight: 600;
-    align-items: center;
     margin: 0;
 
     :root[zen-unsynced-window] & {

surfer.json

@@ -5,8 +5,8 @@
   "binaryName": "zen",
   "version": {
     "product": "firefox",
-    "version": "147.0.1",
+    "version": "147.0.2",
-    "candidate": "147.0.1",
+    "candidate": "147.0.2",
     "candidateBuild": 1
   },
   "buildOptions": {
@@ -20,7 +20,7 @@
       "brandShortName": "Zen",
       "brandFullName": "Zen Browser",
       "release": {
-        "displayVersion": "1.18b",
+        "displayVersion": "1.18.3b",
         "github": {
           "repo": "zen-browser/desktop"
         },
@@ -40,7 +40,7 @@
       "brandShortName": "Twilight",
       "brandFullName": "Zen Twilight",
       "release": {
-        "displayVersion": "1.18t",
+        "displayVersion": "1.19t",
         "github": {
           "repo": "zen-browser/desktop"
         }
@@ -54,4 +54,4 @@
     "licenseType": "MPL-2.0"
   },
   "updateHostname": "updates.zen-browser.app"
-}
+}