feat: Clone the previous state, b=no-bug, c=no-component

Signed-off-by: mr. m <91018726+mr-cheffy@users.noreply.github.com>

prefs/zen/theme.yaml

@@ -36,7 +36,7 @@
   value: '@IS_TWILIGHT@'
 
 - name: zen.theme.hide-unified-extensions-button
-  value: true
+  value: false
 
 # ==== Mark: border radius ====
 

src/browser/base/content/zen-assets.inc.xhtml

@@ -48,7 +48,6 @@
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenFolders.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenMods.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenCompactMode.mjs"></script>
-<script type="text/javascript" src="chrome://browser/content/zen-components/ZenPinnedTabsStorage.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenWorkspacesStorage.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenPinnedTabManager.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenGradientGenerator.mjs"></script>
@@ -58,3 +57,4 @@
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenDownloadAnimation.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenEmojiPicker.mjs"></script>
 <script type="text/javascript" src="chrome://browser/content/zen-components/ZenWorkspaceCreation.mjs"></script>
+<script type="text/javascript" src="chrome://browser/content/zen-components/ZenWindowSyncing.mjs"></script>

src/browser/base/content/zen-assets.jar.inc.mn

@@ -41,6 +41,7 @@
         content/browser/zen-components/ZenWorkspaceIcons.mjs                    (../../zen/workspaces/ZenWorkspaceIcons.mjs)
         content/browser/zen-components/ZenWorkspace.mjs                         (../../zen/workspaces/ZenWorkspace.mjs)
         content/browser/zen-components/ZenWorkspaces.mjs                        (../../zen/workspaces/ZenWorkspaces.mjs)
+        content/browser/zen-components/ZenWindowSyncing.mjs                     (../../zen/workspaces/ZenWindowSyncing.mjs)
         content/browser/zen-components/ZenWorkspaceCreation.mjs                 (../../zen/workspaces/ZenWorkspaceCreation.mjs)
         content/browser/zen-components/ZenWorkspacesStorage.mjs                 (../../zen/workspaces/ZenWorkspacesStorage.mjs)
         content/browser/zen-components/ZenWorkspacesSync.mjs                    (../../zen/workspaces/ZenWorkspacesSync.mjs)
@@ -50,7 +51,6 @@
 
         content/browser/zen-components/ZenKeyboardShortcuts.mjs                 (../../zen/kbs/ZenKeyboardShortcuts.mjs)
 
-        content/browser/zen-components/ZenPinnedTabsStorage.mjs                 (../../zen/tabs/ZenPinnedTabsStorage.mjs)
         content/browser/zen-components/ZenPinnedTabManager.mjs                  (../../zen/tabs/ZenPinnedTabManager.mjs)
 *       content/browser/zen-styles/zen-tabs.css                                 (../../zen/tabs/zen-tabs.css)
         content/browser/zen-styles/zen-tabs/vertical-tabs.css                   (../../zen/tabs/zen-tabs/vertical-tabs.css)

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

@@ -0,0 +1,21 @@
+diff --git a/browser/components/sessionstore/SessionFile.sys.mjs b/browser/components/sessionstore/SessionFile.sys.mjs
+index 31140cb8be3b529a0952ca8dc55165690b0e2120..605c9e0aa84da0a2d3171a0573e8cd95e27bd0c4 100644
+--- a/browser/components/sessionstore/SessionFile.sys.mjs
++++ b/browser/components/sessionstore/SessionFile.sys.mjs
+@@ -22,6 +22,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
+   RunState: "resource:///modules/sessionstore/RunState.sys.mjs",
+   SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
+   SessionWriter: "resource:///modules/sessionstore/SessionWriter.sys.mjs",
++  ZenSessionStore: "resource:///modules/zen/ZenSessionManager.sys.mjs",
+ });
+ 
+ const PREF_UPGRADE_BACKUP = "browser.sessionstore.upgradeBackup.latestBuildID";
+@@ -380,7 +381,7 @@ var SessionFileInternal = {
+     this._readOrigin = result.origin;
+ 
+     result.noFilesFound = noFilesFound;
+-
++    await lazy.ZenSessionStore.readFile();
+     return result;
+   },
+ 

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

@@ -0,0 +1,21 @@
+diff --git a/browser/components/sessionstore/SessionStartup.sys.mjs b/browser/components/sessionstore/SessionStartup.sys.mjs
+index be23213ae9ec7e59358a17276c6c3764d38d9996..ca5a8ccc916ceeab5140f1278d15233cefbe5815 100644
+--- a/browser/components/sessionstore/SessionStartup.sys.mjs
++++ b/browser/components/sessionstore/SessionStartup.sys.mjs
+@@ -40,6 +40,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
+   StartupPerformance:
+     "resource:///modules/sessionstore/StartupPerformance.sys.mjs",
+   sessionStoreLogger: "resource:///modules/sessionstore/SessionLogger.sys.mjs",
++  ZenSessionStore: "resource:///modules/zen/ZenSessionManager.sys.mjs",
+ });
+ 
+ const STATE_RUNNING_STR = "running";
+@@ -179,6 +180,8 @@ export var SessionStartup = {
+       this._initialState = parsed;
+     }
+ 
++    lazy.ZenSessionStore.onFileRead(this._initialState);
++
+     if (this._initialState == null) {
+       // No valid session found.
+       this._sessionType = this.NO_SESSION;

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 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10540eb659 100644
+index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..7cd5b92c1b1ddbaea89de5e9627fc5bc3315aa98 100644
 --- a/browser/components/sessionstore/SessionStore.sys.mjs
 +++ b/browser/components/sessionstore/SessionStore.sys.mjs
 @@ -127,6 +127,8 @@ const TAB_EVENTS = [
@@ -11,7 +11,15 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
  ];
  
  const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
-@@ -1911,6 +1913,8 @@ var SessionStoreInternal = {
+@@ -196,6 +198,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
+   TabStateCache: "resource:///modules/sessionstore/TabStateCache.sys.mjs",
+   TabStateFlusher: "resource:///modules/sessionstore/TabStateFlusher.sys.mjs",
+   setTimeout: "resource://gre/modules/Timer.sys.mjs",
++  ZenSessionStore: "resource:///modules/zen/ZenSessionManager.sys.mjs",
+ });
+ 
+ ChromeUtils.defineLazyGetter(lazy, "blankURI", () => {
+@@ -1911,6 +1914,8 @@ var SessionStoreInternal = {
        case "TabPinned":
        case "TabUnpinned":
        case "SwapDocShells":
@@ -20,7 +28,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
          this.saveStateDelayed(win);
          break;
        case "TabGroupCreate":
-@@ -2151,7 +2155,6 @@ var SessionStoreInternal = {
+@@ -2151,7 +2156,6 @@ var SessionStoreInternal = {
        if (closedWindowState) {
          let newWindowState;
          if (
@@ -28,7 +36,18 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
            !lazy.SessionStartup.willRestore()
          ) {
            // We want to split the window up into pinned tabs and unpinned tabs.
-@@ -2384,11 +2387,9 @@ var SessionStoreInternal = {
+@@ -2215,6 +2219,10 @@ var SessionStoreInternal = {
+       });
+       this._shouldRestoreLastSession = false;
+     }
++    else if (!aInitialState && isRegularWindow) {
++      aInitialState = lazy.ZenSessionStore.getNewWindowData();
++      this.restoreWindows(aWindow, aInitialState, {});
++    }
+ 
+     if (this._restoreLastWindow && aWindow.toolbar.visible) {
+       // always reset (if not a popup window)
+@@ -2384,11 +2392,9 @@ var SessionStoreInternal = {
            tabbrowser.selectedTab.label;
        }
  
@@ -40,7 +59,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
  
        // Store the window's close date to figure out when each individual tab
        // was closed. This timestamp should allow re-arranging data based on how
-@@ -3373,7 +3374,7 @@ var SessionStoreInternal = {
+@@ -3373,7 +3379,7 @@ var SessionStoreInternal = {
      if (!isPrivateWindow && tabState.isPrivate) {
        return;
      }
@@ -49,7 +68,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        return;
      }
  
-@@ -4089,6 +4090,11 @@ var SessionStoreInternal = {
+@@ -4089,6 +4095,11 @@ var SessionStoreInternal = {
          Math.min(tabState.index, tabState.entries.length)
        );
        tabState.pinned = false;
@@ -61,7 +80,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
  
        if (inBackground === false) {
          aWindow.gBrowser.selectedTab = newTab;
-@@ -4525,6 +4531,7 @@ var SessionStoreInternal = {
+@@ -4525,6 +4536,7 @@ var SessionStoreInternal = {
        // Append the tab if we're opening into a different window,
        tabIndex: aSource == aTargetWindow ? pos : Infinity,
        pinned: state.pinned,
@@ -69,7 +88,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        userContextId: state.userContextId,
        skipLoad: true,
        preferredRemoteType,
-@@ -5374,7 +5381,7 @@ var SessionStoreInternal = {
+@@ -5374,7 +5386,7 @@ var SessionStoreInternal = {
  
      for (let i = tabbrowser.pinnedTabCount; i < tabbrowser.tabs.length; i++) {
        let tab = tabbrowser.tabs[i];
@@ -78,7 +97,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
          removableTabs.push(tab);
        }
      }
-@@ -5434,7 +5441,7 @@ var SessionStoreInternal = {
+@@ -5434,7 +5446,7 @@ var SessionStoreInternal = {
      }
  
      let workspaceID = aWindow.getWorkspaceID();
@@ -87,7 +106,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        winData.workspaceID = workspaceID;
      }
    },
-@@ -5625,11 +5632,12 @@ var SessionStoreInternal = {
+@@ -5625,11 +5637,12 @@ var SessionStoreInternal = {
      }
  
      let tabbrowser = aWindow.gBrowser;
@@ -101,7 +120,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
      // update the internal state data for this window
      for (let tab of tabs) {
        if (tab == aWindow.FirefoxViewHandler.tab) {
-@@ -5640,6 +5648,7 @@ var SessionStoreInternal = {
+@@ -5640,6 +5653,7 @@ var SessionStoreInternal = {
        tabsData.push(tabData);
      }
  
@@ -109,7 +128,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
      // update tab group state for this window
      winData.groups = [];
      for (let tabGroup of aWindow.gBrowser.tabGroups) {
-@@ -5652,7 +5661,7 @@ var SessionStoreInternal = {
+@@ -5652,7 +5666,7 @@ 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) {
@@ -118,7 +137,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        winData.title = tabbrowser.tabs[0].label;
      }
      winData.selected = selectedIndex;
-@@ -5764,8 +5773,8 @@ var SessionStoreInternal = {
+@@ -5764,8 +5778,8 @@ var SessionStoreInternal = {
      // selectTab represents.
      let selectTab = 0;
      if (overwriteTabs) {
@@ -129,7 +148,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        selectTab = Math.min(selectTab, winData.tabs.length);
      }
  
-@@ -5808,6 +5817,8 @@ var SessionStoreInternal = {
+@@ -5808,6 +5822,8 @@ var SessionStoreInternal = {
          winData.tabs,
          winData.groups ?? []
        );
@@ -138,7 +157,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
        this._log.debug(
          `restoreWindow, createTabsForSessionRestore returned ${tabs.length} tabs`
        );
-@@ -6371,6 +6382,25 @@ var SessionStoreInternal = {
+@@ -6371,6 +6387,25 @@ var SessionStoreInternal = {
  
      // Most of tabData has been restored, now continue with restoring
      // attributes that may trigger external events.
@@ -152,8 +171,8 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
 +    if (tabData.zenHasStaticLabel) {
 +      tab.setAttribute("zen-has-static-label", "true");
 +    }
-+    if (tabData.zenPinnedId) {
++    if (tabData.zenSyncId) {
-+      tab.setAttribute("zen-pin-id", tabData.zenPinnedId);
++      tab.setAttribute("zen-sync-id", tabData.zenSyncId);
 +    }
 +    if (tabData.zenDefaultUserContextId) {
 +      tab.setAttribute("zenDefaultUserContextId", true);
@@ -164,7 +183,7 @@ index 1cdbc0f41bf5b55dfbbd850cb618c6d870f7a261..f13ed1412bb7ae6623aa2605d7691d10
  
      if (tabData.pinned) {
        tabbrowser.pinTab(tab);
-@@ -7289,7 +7319,7 @@ var SessionStoreInternal = {
+@@ -7289,7 +7324,7 @@ var SessionStoreInternal = {
  
        let groupsToSave = new Map();
        for (let tIndex = 0; tIndex < window.tabs.length; ) {

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

@@ -1,5 +1,5 @@
 diff --git a/browser/components/sessionstore/TabState.sys.mjs b/browser/components/sessionstore/TabState.sys.mjs
-index 82721356d191055bec0d4b0ca49e481221988801..1ea5c394c704da295149443d7794961a12f2060b 100644
+index 82721356d191055bec0d4b0ca49e481221988801..d1323fe17c995611ebdfe2869b0ccd2d45bcfa11 100644
 --- a/browser/components/sessionstore/TabState.sys.mjs
 +++ b/browser/components/sessionstore/TabState.sys.mjs
 @@ -85,7 +85,22 @@ class _TabState {
@@ -7,7 +7,7 @@ index 82721356d191055bec0d4b0ca49e481221988801..1ea5c394c704da295149443d7794961a
      }
  
 +    tabData.zenWorkspace = tab.getAttribute("zen-workspace-id");
-+    tabData.zenPinnedId = tab.getAttribute("zen-pin-id");
++    tabData.zenSyncId = tab.getAttribute("zen-sync-id");
 +    tabData.zenEssential = tab.getAttribute("zen-essential");
 +    tabData.pinned = tabData.pinned || tabData.zenEssential;
 +    tabData.zenDefaultUserContextId = tab.getAttribute("zenDefaultUserContextId");

src/browser/components/tabbrowser/content/drag-and-drop-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/drag-and-drop.js b/browser/components/tabbrowser/content/drag-and-drop.js
-index c97c661656868bc7faaf7c66c9702eea056aafe1..3a2b4bd1a017697539a3b81432199812307b9a04 100644
+index c97c661656868bc7faaf7c66c9702eea056aafe1..aa9f0ed071e4898cac2b98a4d81e95df6a41b8dd 100644
 --- a/browser/components/tabbrowser/content/drag-and-drop.js
 +++ b/browser/components/tabbrowser/content/drag-and-drop.js
 @@ -32,6 +32,9 @@
@@ -149,8 +149,8 @@ index c97c661656868bc7faaf7c66c9702eea056aafe1..3a2b4bd1a017697539a3b81432199812
          this.#tabbrowserTabs.verticalMode &&
 -        tab.pinned &&
 -        this.#tabbrowserTabs.hasAttribute("expanded") &&
-+        tab.hasAttribute("zen-essential") &&
++        (tab.hasAttribute("zen-essential")) &&
-+        (this.#tabbrowserTabs.hasAttribute("expanded") || document.documentElement.hasAttribute("zen-sidebar-expanded")) &&
++        (this.hasAttribute("expanded") || document.documentElement.hasAttribute("zen-sidebar-expanded")) &&
          !this.#tabbrowserTabs.expandOnHover
        );
      }

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

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tab.js b/browser/components/tabbrowser/content/tab.js
-index 4c1a48424316b29d27ae2bc8b64004df41c87bb6..f1ff9bf0947127a8e9115357cedac577b5fad08c 100644
+index 4c1a48424316b29d27ae2bc8b64004df41c87bb6..ce54ed0c8a93d5521a436c55c9432c090b0420ac 100644
 --- a/browser/components/tabbrowser/content/tab.js
 +++ b/browser/components/tabbrowser/content/tab.js
 @@ -21,6 +21,7 @@
@@ -121,15 +121,7 @@ index 4c1a48424316b29d27ae2bc8b64004df41c87bb6..f1ff9bf0947127a8e9115357cedac577
      on_click(event) {
        if (event.button != 0) {
          return;
-@@ -572,6 +594,7 @@
+@@ -584,6 +606,14 @@
-             )
-           );
-         } else {
-+          gZenPinnedTabManager._removePinnedAttributes(this, true);
-           gBrowser.removeTab(this, {
-             animate: true,
-             triggeringEvent: event,
-@@ -584,6 +607,14 @@
          // (see tabbrowser-tabs 'click' handler).
          gBrowser.tabContainer._blockDblClick = true;
        }
@@ -144,7 +136,7 @@ index 4c1a48424316b29d27ae2bc8b64004df41c87bb6..f1ff9bf0947127a8e9115357cedac577
      }
  
      on_dblclick(event) {
-@@ -607,6 +638,8 @@
+@@ -607,6 +637,8 @@
            animate: true,
            triggeringEvent: event,
          });

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 c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad0c761fb5 100644
+index c0eafd4faf8d57b8486c5bf8917375850ec8147e..30c8fd7e978eb3036f35b17ae3f6ea4cd44d980e 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -450,15 +450,64 @@
@@ -420,10 +420,10 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
 +            gZenWorkspaces._initialTab._shouldRemove = true;
 +          }
 +        }
-       }
++      }
 +      else {
 +        gZenWorkspaces._tabToRemoveForEmpty = this.selectedTab;
-+      }
+       }
 +      this._hasAlreadyInitializedZenSessionStore = true;
  
        if (tabs.length > 1 || !tabs[0].selected) {
@@ -498,17 +498,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
  
        TabBarVisibility.update();
      }
-@@ -4635,6 +4763,9 @@
+@@ -4896,6 +5024,7 @@
-         return;
-       }
- 
-+      for (let tab of selectedTabs) {
-+        gZenPinnedTabManager._removePinnedAttributes(tab, true);
-+      }
-       this.removeTabs(selectedTabs, { isUserTriggered, telemetrySource });
-     }
- 
-@@ -4896,6 +5027,7 @@
          telemetrySource,
        } = {}
      ) {
@@ -516,7 +506,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        // When 'closeWindowWithLastTab' pref is enabled, closing all tabs
        // can be considered equivalent to closing the window.
        if (
-@@ -4985,6 +5117,7 @@
+@@ -4985,6 +5114,7 @@
          if (lastToClose) {
            this.removeTab(lastToClose, aParams);
          }
@@ -524,7 +514,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        } catch (e) {
          console.error(e);
        }
-@@ -5023,6 +5156,12 @@
+@@ -5023,6 +5153,12 @@
          aTab._closeTimeNoAnimTimerId = Glean.browserTabclose.timeNoAnim.start();
        }
  
@@ -537,7 +527,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        // Handle requests for synchronously removing an already
        // asynchronously closing tab.
        if (!animate && aTab.closing) {
-@@ -5037,6 +5176,9 @@
+@@ -5037,6 +5173,9 @@
        // state).
        let tabWidth = window.windowUtils.getBoundsWithoutFlushing(aTab).width;
        let isLastTab = this.#isLastTabInWindow(aTab);
@@ -547,7 +537,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        if (
          !this._beginRemoveTab(aTab, {
            closeWindowFastpath: true,
-@@ -5085,7 +5227,13 @@
+@@ -5085,7 +5224,13 @@
          // We're not animating, so we can cancel the animation stopwatch.
          Glean.browserTabclose.timeAnim.cancel(aTab._closeTimeAnimTimerId);
          aTab._closeTimeAnimTimerId = null;
@@ -562,7 +552,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
          return;
        }
  
-@@ -5219,7 +5367,7 @@
+@@ -5219,7 +5364,7 @@
            closeWindowWithLastTab != null
              ? closeWindowWithLastTab
              : !window.toolbar.visible ||
@@ -571,7 +561,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
  
          if (closeWindow) {
            // We've already called beforeunload on all the relevant tabs if we get here,
-@@ -5243,6 +5391,7 @@
+@@ -5243,6 +5388,7 @@
  
          newTab = true;
        }
@@ -579,7 +569,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        aTab._endRemoveArgs = [closeWindow, newTab];
  
        // swapBrowsersAndCloseOther will take care of closing the window without animation.
-@@ -5283,13 +5432,7 @@
+@@ -5283,13 +5429,7 @@
        aTab._mouseleave();
  
        if (newTab) {
@@ -594,7 +584,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        } else {
          TabBarVisibility.update();
        }
-@@ -5422,6 +5565,7 @@
+@@ -5422,6 +5562,7 @@
          this.tabs[i]._tPos = i;
        }
  
@@ -602,7 +592,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        if (!this._windowIsClosing) {
          // update tab close buttons state
          this.tabContainer._updateCloseButtons();
-@@ -5643,6 +5787,7 @@
+@@ -5643,6 +5784,7 @@
        }
  
        let excludeTabs = new Set(aExcludeTabs);
@@ -610,7 +600,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
  
        // If this tab has a successor, it should be selectable, since
        // hiding or closing a tab removes that tab as a successor.
-@@ -5655,13 +5800,13 @@
+@@ -5655,13 +5797,13 @@
          !excludeTabs.has(aTab.owner) &&
          Services.prefs.getBoolPref("browser.tabs.selectOwnerOnClose")
        ) {
@@ -626,7 +616,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        );
  
        let tab = this.tabContainer.findNextTab(aTab, {
-@@ -5677,7 +5822,7 @@
+@@ -5677,7 +5819,7 @@
        }
  
        if (tab) {
@@ -635,7 +625,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        }
  
        // If no qualifying visible tab was found, see if there is a tab in
-@@ -5698,7 +5843,7 @@
+@@ -5698,7 +5840,7 @@
          });
        }
  
@@ -644,7 +634,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
      }
  
      _blurTab(aTab) {
-@@ -6104,10 +6249,10 @@
+@@ -6104,10 +6246,10 @@
        SessionStore.deleteCustomTabValue(aTab, "hiddenBy");
      }
  
@@ -657,7 +647,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
          aTab.selected ||
          aTab.closing ||
          // Tabs that are sharing the screen, microphone or camera cannot be hidden.
-@@ -6166,6 +6311,7 @@
+@@ -6166,6 +6308,7 @@
       * @param {MozTabbrowserTab|MozTabbrowserTabGroup|MozTabbrowserTabGroup.labelElement} aTab
       */
      replaceTabWithWindow(aTab, aOptions) {
@@ -665,7 +655,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        if (this.tabs.length == 1) {
          return null;
        }
-@@ -6299,7 +6445,7 @@
+@@ -6299,7 +6442,7 @@
       *   `true` if element is a `<tab-group>`
       */
      isTabGroup(element) {
@@ -674,7 +664,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
      }
  
      /**
-@@ -6375,8 +6521,8 @@
+@@ -6375,8 +6518,8 @@
        }
  
        // Don't allow mixing pinned and unpinned tabs.
@@ -685,7 +675,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        } else {
          tabIndex = Math.max(tabIndex, this.pinnedTabCount);
        }
-@@ -6402,10 +6548,16 @@
+@@ -6402,10 +6545,16 @@
        this.#handleTabMove(
          element,
          () => {
@@ -704,7 +694,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
            if (neighbor && this.isTab(element) && tabIndex > element._tPos) {
              neighbor.after(element);
            } else {
-@@ -6463,23 +6615,28 @@
+@@ -6463,23 +6612,28 @@
      #moveTabNextTo(element, targetElement, moveBefore = false, metricsContext) {
        if (this.isTabGroupLabel(targetElement)) {
          targetElement = targetElement.group;
@@ -739,7 +729,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        } 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
-@@ -6492,14 +6649,34 @@
+@@ -6492,14 +6646,34 @@
          //    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.
@@ -775,7 +765,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
          element.pinned
            ? this.tabContainer.pinnedTabsContainer
            : this.tabContainer;
-@@ -6508,7 +6685,7 @@
+@@ -6508,7 +6682,7 @@
          element,
          () => {
            if (moveBefore) {
@@ -784,7 +774,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
            } else if (targetElement) {
              targetElement.after(element);
            } else {
-@@ -6580,10 +6757,10 @@
+@@ -6580,10 +6754,10 @@
       * @param {TabMetricsContext} [metricsContext]
       */
      moveTabToGroup(aTab, aGroup, metricsContext) {
@@ -797,7 +787,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
          return;
        }
        if (aTab.group && aTab.group.id === aGroup.id) {
-@@ -6613,6 +6790,7 @@
+@@ -6613,6 +6787,7 @@
  
        let state = {
          tabIndex: tab._tPos,
@@ -805,7 +795,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        };
        if (tab.visible) {
          state.elementIndex = tab.elementIndex;
-@@ -6639,7 +6817,7 @@
+@@ -6639,7 +6814,7 @@
        let changedTabGroup =
          previousTabState.tabGroupId != currentTabState.tabGroupId;
  
@@ -814,7 +804,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
          tab.dispatchEvent(
            new CustomEvent("TabMove", {
              bubbles: true,
-@@ -6676,6 +6854,10 @@
+@@ -6676,6 +6851,10 @@
  
        moveActionCallback();
  
@@ -825,7 +815,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
        // Clear tabs cache after moving nodes because the order of tabs may have
        // changed.
        this.tabContainer._invalidateCachedTabs();
-@@ -7576,7 +7758,7 @@
+@@ -7576,7 +7755,7 @@
              // preventDefault(). It will still raise the window if appropriate.
              break;
            }
@@ -834,7 +824,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
            window.focus();
            aEvent.preventDefault();
            break;
-@@ -7593,7 +7775,6 @@
+@@ -7593,7 +7772,6 @@
          }
          case "TabGroupCollapse":
            aEvent.target.tabs.forEach(tab => {
@@ -842,7 +832,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
            });
            break;
          case "TabGroupCreateByUser":
-@@ -8542,6 +8723,7 @@
+@@ -8542,6 +8720,7 @@
              aWebProgress.isTopLevel
            ) {
              this.mTab.setAttribute("busy", "true");
@@ -850,7 +840,7 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
              gBrowser._tabAttrModified(this.mTab, ["busy"]);
              this.mTab._notselectedsinceload = !this.mTab.selected;
            }
-@@ -9543,7 +9725,7 @@ var TabContextMenu = {
+@@ -9543,7 +9722,7 @@ var TabContextMenu = {
      );
      contextUnpinSelectedTabs.hidden =
        !this.contextTab.pinned || !this.multiselected;
@@ -859,11 +849,3 @@ index c0eafd4faf8d57b8486c5bf8917375850ec8147e..2ab3908f421d6bc126eb7a0f886646ad
      // Build Ask Chat items
      TabContextMenu.GenAI.buildTabMenu(
        document.getElementById("context_askChat"),
-@@ -9863,6 +10045,7 @@ var TabContextMenu = {
-         )
-       );
-     } else {
-+      gZenPinnedTabManager._removePinnedAttributes(this.contextTab, true);
-       gBrowser.removeTab(this.contextTab, {
-         animate: true,
-         ...gBrowser.TabMetrics.userTriggeredContext(

src/zen/ZenComponents.manifest

@@ -13,3 +13,4 @@
 category app-startup nsBrowserGlue @mozilla.org/browser/browserglue;1 application={ec8030f7-c20a-464f-9b0e-13a3a9e97384}
 
 #include common/Components.manifest
+#include sessionstore/SessionComponents.manifest

src/zen/common/ZenSessionStore.mjs

@@ -15,8 +15,8 @@
       if (tabData.zenWorkspace) {
         tab.setAttribute('zen-workspace-id', tabData.zenWorkspace);
       }
-      if (tabData.zenPinnedId) {
+      if (tabData.zenSyncId) {
-        tab.setAttribute('zen-pin-id', tabData.zenPinnedId);
+        tab.setAttribute('zen-sync-id', tabData.zenSyncId);
       }
       if (tabData.zenHasStaticLabel) {
         tab.setAttribute('zen-has-static-label', 'true');

src/zen/common/ZenUIManager.mjs

@@ -1303,14 +1303,6 @@ var gZenVerticalTabsManager = {
         } else {
           gBrowser.setTabTitle(this._tabEdited);
         }
-        if (this._tabEdited.getAttribute('zen-pin-id')) {
-          // Update pin title in storage
-          await gZenPinnedTabManager.updatePinTitle(
-            this._tabEdited,
-            this._tabEdited.label,
-            !!newName
-          );
-        }
 
         // Maybe add some confetti here?!?
         gZenUIManager.motion.animate(

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

@@ -5,7 +5,7 @@
  */
 :root:not([inDOMFullscreen='true']):not([chromehidden~='location']):not([chromehidden~='toolbar']) {
   & #tabbrowser-tabbox #tabbrowser-tabpanels .browserSidebarContainer {
-    overflow-y: clip;
+    overflow: clip;
 
     :root:not([zen-no-padding='true']) &:not(.zen-glance-overlay) {
       border-radius: var(--zen-native-inner-radius);

src/zen/common/styles/zen-single-components.css

@@ -492,7 +492,7 @@ body > #confetti {
   }
 }
 
-@media -moz-pref('zen.theme.hide-unified-extensions-button') {
+@media (-moz-pref('zen.theme.hide-unified-extensions-button')) {
   #unified-extensions-button {
     display: none !important;
   }

src/zen/folders/ZenFolder.mjs

@@ -150,7 +150,6 @@
       for (let tab of this.allItems.reverse()) {
         tab = tab.group.hasAttribute('split-view-group') ? tab.group : tab;
         if (tab.hasAttribute('zen-empty-tab')) {
-          await ZenPinnedTabsStorage.removePin(tab.getAttribute('zen-pin-id'));
           gBrowser.removeTab(tab);
         } else {
           gBrowser.ungroupTab(tab);
@@ -160,7 +159,6 @@
 
     async delete() {
       for (const tab of this.allItemsRecursive) {
-        await ZenPinnedTabsStorage.removePin(tab.getAttribute('zen-pin-id'));
         if (tab.hasAttribute('zen-empty-tab')) {
           // Manually remove the empty tabs as removeTabs() inside removeTabGroup
           // does ignore them.

src/zen/folders/ZenFolders.mjs

@@ -508,9 +508,6 @@
       tabs = [emptyTab, ...filteredTabs];
 
       const folder = this._createFolderNode(options);
-      if (options.initialPinId) {
-        folder.setAttribute('zen-pin-id', options.initialPinId);
-      }
 
       if (options.insertAfter) {
         options.insertAfter.after(folder);
@@ -940,7 +937,7 @@
         if (!parentFolder && folder.hasAttribute('split-view-group')) continue;
         const emptyFolderTabs = folder.tabs
           .filter((tab) => tab.hasAttribute('zen-empty-tab'))
-          .map((tab) => tab.getAttribute('zen-pin-id'));
+          .map((tab) => tab.getAttribute('zen-sync-id'));
 
         let prevSiblingInfo = null;
         const prevSibling = folder.previousElementSibling;
@@ -949,8 +946,8 @@
         if (prevSibling) {
           if (gBrowser.isTabGroup(prevSibling)) {
             prevSiblingInfo = { type: 'group', id: prevSibling.id };
-          } else if (gBrowser.isTab(prevSibling) && prevSibling.hasAttribute('zen-pin-id')) {
+          } else if (gBrowser.isTab(prevSibling) && prevSibling.hasAttribute('zen-sync-id')) {
-            const zenPinId = prevSibling.getAttribute('zen-pin-id');
+            const zenPinId = prevSibling.getAttribute('zen-sync-id');
             prevSiblingInfo = { type: 'tab', id: zenPinId };
           } else {
             prevSiblingInfo = { type: 'start', id: null };
@@ -969,7 +966,7 @@
           prevSiblingInfo: prevSiblingInfo,
           emptyTabIds: emptyFolderTabs,
           userIcon: userIcon?.getAttribute('href'),
-          pinId: folder.getAttribute('zen-pin-id'),
+          syncId: folder.getAttribute('zen-sync-id'),
           // note: We shouldn't be using the workspace-id anywhere, we are just
           //  remembering it for the pinned tabs manager to use it later.
           workspaceId: folder.getAttribute('zen-workspace-id'),
@@ -996,9 +993,9 @@
         tabFolderWorkingData.set(folderData.id, workingData);
 
         const oldGroup = document.getElementById(folderData.id);
-        folderData.emptyTabIds.forEach((zenPinId) => {
+        folderData.emptyTabIds.forEach((zenSyncId) => {
           oldGroup
-            ?.querySelector(`tab[zen-pin-id="${zenPinId}"]`)
+            ?.querySelector(`tab[zen-sync-id="${zenSyncId}"]`)
             ?.setAttribute('zen-empty-tab', true);
         });
         if (oldGroup) {
@@ -1011,7 +1008,7 @@
               saveOnWindowClose: folderData.saveOnWindowClose,
               workspaceId: folderData.workspaceId,
             });
-            folder.setAttribute('zen-pin-id', folderData.pinId);
+            folder.setAttribute('zen-sync-id', folderData.syncId);
             workingData.node = folder;
             oldGroup.before(folder);
           } else {
@@ -1044,7 +1041,7 @@
             switch (stateData?.prevSiblingInfo?.type) {
               case 'tab': {
                 const tab = parentWorkingData.node.querySelector(
-                  `[zen-pin-id="${stateData.prevSiblingInfo.id}"]`
+                  `[zen-sync-id="${stateData.prevSiblingInfo.id}"]`
                 );
                 tab.after(node);
                 break;
@@ -1156,7 +1153,10 @@
       let dragDownThreshold =
         Services.prefs.getIntPref('zen.view.drag-and-drop.drop-inside-lower-threshold') / 100;
 
-      const dropElementGroup = dropElement;
+      const dropElementGroup = dropElement.group;
+      if (!dropElementGroup) {
+        return { dropElement, colorCode, dropBefore };
+      }
       const isSplitGroup = dropElement?.group?.hasAttribute('split-view-group');
       let firstGroupElem =
         dropElementGroup.querySelector('.zen-tab-group-start').nextElementSibling;

src/zen/moz.build

@@ -13,4 +13,5 @@ DIRS += [
     "tests",
     "urlbar",
     "toolkit",
+    "sessionstore",
 ]

src/zen/sessionstore/SessionComponents.manifest

@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Browser global components initializing before UI startup
+category browser-before-ui-startup resource:///modules/zen/ZenSessionManager.sys.mjs ZenSessionStore.init

src/zen/sessionstore/ZenSessionFile.sys.mjs

@@ -0,0 +1,40 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Note that changing this hidden pref will make the previous session file
+// unused, causing a new session file to be created on next write.
+const SHOULD_COMPRESS_FILE = Services.prefs.getBoolPref('zen.session-store.compress-file', true);
+
+const FILE_NAME = SHOULD_COMPRESS_FILE ? 'zen-sessions.jsonlz4' : 'zen-sessions.json';
+
+export class nsZenSessionFile {
+  #path = PathUtils.join(PathUtils.profileDir, FILE_NAME);
+  #sidebar = [];
+
+  async read() {
+    try {
+      const data = await IOUtils.readJSON(this.#path, { compress: SHOULD_COMPRESS_FILE });
+      this.#sidebar = data.sidebar || [];
+    } catch {
+      // File doesn't exist yet, that's fine.
+    }
+  }
+
+  get sidebar() {
+    return this.#sidebar;
+  }
+
+  set sidebar(data) {
+    this.#sidebar = data;
+  }
+
+  async #write(data) {
+    await IOUtils.writeJSON(this.#path, data, { compress: SHOULD_COMPRESS_FILE });
+  }
+
+  async store() {
+    const data = { sidebar: this.#sidebar };
+    await this.#write(data);
+  }
+}

src/zen/sessionstore/ZenSessionManager.sys.mjs

@@ -0,0 +1,167 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  nsZenSessionFile: 'resource:///modules/zen/ZenSessionFile.sys.mjs',
+  PrivateBrowsingUtils: 'resource://gre/modules/PrivateBrowsingUtils.sys.mjs',
+  BrowserWindowTracker: 'resource:///modules/BrowserWindowTracker.sys.mjs',
+  TabGroupState: 'resource:///modules/sessionstore/TabGroupState.sys.mjs',
+  SessionStore: 'resource:///modules/sessionstore/SessionStore.sys.mjs',
+  SessionSaver: 'resource:///modules/sessionstore/SessionSaver.sys.mjs',
+});
+
+const LAZY_COLLECT_THRESHOLD = 5 * 60 * 1000; // 5 minutes
+const OBSERVING = ['sessionstore-state-write-complete', 'browser-window-before-show'];
+
+class nsZenSessionManager {
+  #file;
+
+  constructor() {
+    this.#file = new lazy.nsZenSessionFile();
+  }
+
+  // Called from SessionComponents.manifest on app-startup
+  init() {
+    this.#initObservers();
+  }
+
+  async readFile() {
+    await this.#file.read();
+  }
+
+  onFileRead(initialState) {
+    for (const winData of initialState.windows || []) {
+      this.restoreWindowData(winData);
+    }
+  }
+
+  #initObservers() {
+    for (let topic of OBSERVING) {
+      Services.obs.addObserver(this, topic);
+    }
+  }
+
+  get #sidebar() {
+    return this.#file.sidebar;
+  }
+
+  set #sidebar(data) {
+    this.#file.sidebar = data;
+  }
+
+  observe(aSubject, aTopic) {
+    switch (aTopic) {
+      case 'sessionstore-state-write-complete': {
+        this.#saveState(true);
+        break;
+      }
+      case 'browser-window-before-show': // catch new windows
+        this.#onBeforeBrowserWindowShown(aSubject);
+        break;
+      default:
+        break;
+    }
+  }
+
+  /** Handles the browser-window-before-show observer notification. */
+  #onBeforeBrowserWindowShown(aWindow) {
+    // TODO: Initialize new window
+    void aWindow;
+  }
+
+  get #topMostWindow() {
+    return lazy.BrowserWindowTracker.getTopWindow();
+  }
+
+  /**
+   * Saves the current session state. Collects data and writes to disk.
+   *
+   * @param forceUpdateAllWindows (optional)
+   *        Forces us to recollect data for all windows and will bypass and
+   *        update the corresponding caches.
+   */
+  async #saveState(forceUpdateAllWindows = false) {
+    if (lazy.PrivateBrowsingUtils.permanentPrivateBrowsing) {
+      // Don't save (or even collect) anything in permanent private
+      // browsing mode
+      return;
+    }
+    // Collect an initial snapshot of window data before we do the flush.
+    const window = this.#topMostWindow;
+    // We don't have any normal windows or no windows at all
+    if (!window) {
+      return;
+    }
+    this.#collectWindowData(this.#topMostWindow, forceUpdateAllWindows);
+    this.#file.store();
+  }
+
+  /**
+   * Collects session data for a given window.
+   *
+   * @param window
+   *        The window to collect data for.
+   * @param forceUpdate
+   *        Forces us to recollect data and will bypass and update the
+   *        corresponding caches.
+   */
+  #collectWindowData(window, forceUpdate = false) {
+    let sidebarData = this.#sidebar;
+    if (!sidebarData || forceUpdate) {
+      sidebarData = {};
+    }
+
+    // If it hasn't changed, don't update.
+    if (
+      !forceUpdate &&
+      sidebarData.lastCollected &&
+      Date.now() - sidebarData.lastCollected < LAZY_COLLECT_THRESHOLD
+    ) {
+      return;
+    }
+    sidebarData.lastCollected = Date.now();
+    this.#collectTabsData(window, sidebarData);
+    this.#sidebar = sidebarData;
+  }
+
+  /**
+   * Collects session data for all tabs in a given window.
+   *
+   * @param aWindow
+   *        The window to collect tab data for.
+   * @param winData
+   *        The window data object to populate.
+   */
+  #collectTabsData(aWindow, sidebarData) {
+    const winData = lazy.SessionStore.getWindowState(aWindow).windows[0];
+    if (!winData) return;
+    sidebarData.tabs = winData.tabs;
+    sidebarData.folders = winData.folders;
+    sidebarData.splitViewData = winData.splitViewData;
+    sidebarData.groups = winData.groups;
+  }
+
+  restoreWindowData(aWindowData) {
+    const sidebar = this.#file.sidebar;
+    if (!sidebar) {
+      return;
+    }
+    aWindowData.tabs = sidebar.tabs || [];
+    aWindowData.splitViewData = sidebar.splitViewData;
+    aWindowData.folders = sidebar.folders;
+    aWindowData.groups = sidebar.groups;
+  }
+
+  getNewWindowData() {
+    lazy.SessionSaver.run();
+    const state = lazy.SessionStore.getCurrentState(true);
+    const windows = state.windows || {};
+    let newWindow = Cu.cloneInto(windows[0], {});
+    return { windows: [newWindow] };
+  }
+}
+
+export const ZenSessionStore = new nsZenSessionManager();

src/zen/sessionstore/moz.build

@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXTRA_JS_MODULES.zen += [
+  "ZenSessionFile.sys.mjs",
+  "ZenSessionManager.sys.mjs",
+]

src/zen/tabs/ZenPinnedTabManager.mjs

@@ -5,23 +5,7 @@
   const lazy = {};
 
   class ZenPinnedTabsObserver {
-    static ALL_EVENTS = [
+    static ALL_EVENTS = ['TabPinned', 'TabUnpinned'];
-      'TabPinned',
-      'TabUnpinned',
-      'TabMove',
-      'TabGroupCreate',
-      'TabGroupRemoved',
-      'TabGroupMoved',
-      'ZenFolderRenamed',
-      'ZenFolderIconChanged',
-      'TabGroupCollapse',
-      'TabGroupExpand',
-      'TabGrouped',
-      'TabUngrouped',
-      'ZenFolderChangedWorkspace',
-      'TabAddedToEssentials',
-      'TabRemovedFromEssentials',
-    ];
 
     #listeners = [];
 
@@ -101,24 +85,12 @@
     }
 
     onTabIconChanged(tab, url = null) {
+      tab.dispatchEvent(new CustomEvent('ZenTabIconChanged', { bubbles: true, detail: { tab } }));
       const iconUrl = url ?? tab.iconImage.src;
-      if (!iconUrl && tab.hasAttribute('zen-pin-id')) {
-        try {
-          setTimeout(async () => {
-            const favicon = await this.getFaviconAsBase64(tab.linkedBrowser.currentURI);
-            if (favicon) {
-              gBrowser.setIcon(tab, favicon);
-            }
-          });
-        } catch {
-          // Handle error
-        }
-      } else {
       if (tab.hasAttribute('zen-essential')) {
         tab.style.setProperty('--zen-essential-tab-icon', `url(${iconUrl})`);
       }
     }
-    }
 
     _onTabResetPinButton(event, tab) {
       event.stopPropagation();
@@ -148,261 +120,6 @@
       return lazy.zenTabsEssentialsMax;
     }
 
-    async refreshPinnedTabs({ init = false } = {}) {
-      if (!this.enabled) {
-        return;
-      }
-      await ZenPinnedTabsStorage.promiseInitialized;
-      await this.#initializePinsCache();
-      setTimeout(async () => {
-        // Execute in a separate task to avoid blocking the main thread
-        await SessionStore.promiseAllWindowsRestored;
-        await gZenWorkspaces.promiseInitialized;
-        await this.#initializePinnedTabs(init);
-        if (init) {
-          this._hasFinishedLoading = true;
-        }
-      }, 10);
-    }
-
-    async #initializePinsCache() {
-      try {
-        // Get pin data
-        const pins = await ZenPinnedTabsStorage.getPins();
-
-        // Enhance pins with favicons
-        this._pinsCache = await Promise.all(
-          pins.map(async (pin) => {
-            try {
-              if (pin.isGroup) {
-                return pin; // Skip groups for now
-              }
-              const image = await this.getFaviconAsBase64(Services.io.newURI(pin.url));
-              return {
-                ...pin,
-                iconUrl: image || null,
-              };
-            } catch {
-              // If favicon fetch fails, continue without icon
-              return {
-                ...pin,
-                iconUrl: null,
-              };
-            }
-          })
-        );
-      } catch (ex) {
-        console.error('Failed to initialize pins cache:', ex);
-        this._pinsCache = [];
-      }
-
-      this.log(`Initialized pins cache with ${this._pinsCache.length} pins`);
-      return this._pinsCache;
-    }
-
-    #finishedInitializingPins() {
-      if (this.hasInitializedPins) {
-        return;
-      }
-      this._resolvePinnedInitializedInternal();
-      delete this._resolvePinnedInitializedInternal;
-      this.hasInitializedPins = true;
-    }
-
-    async #initializePinnedTabs(init = false) {
-      const pins = this._pinsCache;
-      if (!pins?.length || !init) {
-        this.#finishedInitializingPins();
-        return;
-      }
-
-      const pinnedTabsByUUID = new Map();
-      const pinsToCreate = new Set(pins.map((p) => p.uuid));
-
-      // First pass: identify existing tabs and remove those without pins
-      for (let tab of gZenWorkspaces.allStoredTabs) {
-        const pinId = tab.getAttribute('zen-pin-id');
-        if (!pinId) {
-          continue;
-        }
-
-        if (pinsToCreate.has(pinId)) {
-          // This is a valid pinned tab that matches a pin
-          pinnedTabsByUUID.set(pinId, tab);
-          pinsToCreate.delete(pinId);
-
-          if (lazy.zenPinnedTabRestorePinnedTabsToPinnedUrl && init) {
-            this._resetTabToStoredState(tab);
-          }
-        } else {
-          // This is a pinned tab that no longer has a corresponding pin
-          gBrowser.removeTab(tab);
-        }
-      }
-
-      for (const group of gZenWorkspaces.allTabGroups) {
-        const pinId = group.getAttribute('zen-pin-id');
-        if (!pinId) {
-          continue;
-        }
-        if (pinsToCreate.has(pinId)) {
-          // This is a valid pinned group that matches a pin
-          pinsToCreate.delete(pinId);
-        }
-      }
-
-      // Second pass: For every existing tab, update its label
-      // and set 'zen-has-static-label' attribute if it's been edited
-      for (let pin of pins) {
-        const tab = pinnedTabsByUUID.get(pin.uuid);
-        if (!tab) {
-          continue;
-        }
-
-        tab.removeAttribute('zen-has-static-label'); // So we can set it again
-        if (pin.title && pin.editedTitle) {
-          gBrowser._setTabLabel(tab, pin.title, { beforeTabOpen: true });
-          tab.setAttribute('zen-has-static-label', 'true');
-        }
-      }
-
-      const groups = new Map();
-      const pendingTabsInsideGroups = {};
-
-      // Third pass: create new tabs for pins that don't have tabs
-      for (let pin of pins) {
-        try {
-          if (!pinsToCreate.has(pin.uuid)) {
-            continue; // Skip pins that already have tabs
-          }
-
-          if (pin.isGroup) {
-            const tabs = [];
-            // If there's already existing tabs, let's use them
-            for (const [uuid, existingTab] of pinnedTabsByUUID) {
-              const pinObject = this._pinsCache.find((p) => p.uuid === uuid);
-              if (pinObject && pinObject.parentUuid === pin.uuid) {
-                tabs.push(existingTab);
-              }
-            }
-            // We still need to iterate through pending tabs since the database
-            // query doesn't guarantee the order of insertion
-            for (const [parentUuid, folderTabs] of Object.entries(pendingTabsInsideGroups)) {
-              if (parentUuid === pin.uuid) {
-                tabs.push(...folderTabs);
-              }
-            }
-            const group = gZenFolders.createFolder(tabs, {
-              label: pin.title,
-              collapsed: pin.isFolderCollapsed,
-              initialPinId: pin.uuid,
-              workspaceId: pin.workspaceUuid,
-              insertAfter:
-                groups.get(pin.parentUuid)?.querySelector('.tab-group-container')?.lastChild ||
-                null,
-            });
-            gZenFolders.setFolderUserIcon(group, pin.folderIcon);
-            groups.set(pin.uuid, group);
-            continue;
-          }
-
-          let params = {
-            skipAnimation: true,
-            allowInheritPrincipal: false,
-            skipBackgroundNotify: true,
-            userContextId: pin.containerTabId || 0,
-            createLazyBrowser: true,
-            skipLoad: true,
-            noInitialLabel: false,
-          };
-
-          // Create and initialize the tab
-          let newTab = gBrowser.addTrustedTab(pin.url, params);
-          newTab.setAttribute('zenDefaultUserContextId', true);
-
-          // Set initial label/title
-          if (pin.title) {
-            gBrowser.setInitialTabTitle(newTab, pin.title);
-          }
-
-          // Set the icon if we have it cached
-          if (pin.iconUrl) {
-            gBrowser.setIcon(newTab, pin.iconUrl);
-          }
-
-          newTab.setAttribute('zen-pin-id', pin.uuid);
-
-          if (pin.workspaceUuid) {
-            newTab.setAttribute('zen-workspace-id', pin.workspaceUuid);
-          }
-
-          if (pin.isEssential) {
-            newTab.setAttribute('zen-essential', 'true');
-          }
-
-          if (pin.editedTitle) {
-            newTab.setAttribute('zen-has-static-label', 'true');
-          }
-
-          // Initialize browser state if needed
-          if (!newTab.linkedBrowser._remoteAutoRemoved) {
-            let state = {
-              entries: [
-                {
-                  url: pin.url,
-                  title: pin.title,
-                  triggeringPrincipal_base64: E10SUtils.SERIALIZED_SYSTEMPRINCIPAL,
-                },
-              ],
-              userContextId: pin.containerTabId || 0,
-              image: pin.iconUrl,
-            };
-
-            SessionStore.setTabState(newTab, state);
-          }
-
-          this.log(`Created new pinned tab for pin ${pin.uuid} (isEssential: ${pin.isEssential})`);
-          gBrowser.pinTab(newTab);
-
-          if (pin.parentUuid) {
-            const parentGroup = groups.get(pin.parentUuid);
-            if (parentGroup) {
-              parentGroup.querySelector('.tab-group-container').appendChild(newTab);
-            } else {
-              if (pendingTabsInsideGroups[pin.parentUuid]) {
-                pendingTabsInsideGroups[pin.parentUuid].push(newTab);
-              } else {
-                pendingTabsInsideGroups[pin.parentUuid] = [newTab];
-              }
-            }
-          } else {
-            if (!pin.isEssential) {
-              const container = gZenWorkspaces.workspaceElement(
-                pin.workspaceUuid
-              )?.pinnedTabsContainer;
-              if (container) {
-                container.insertBefore(newTab, container.lastChild);
-              }
-            } else {
-              gZenWorkspaces.getEssentialsSection(pin.containerTabId).appendChild(newTab);
-            }
-          }
-
-          gBrowser.tabContainer._invalidateCachedTabs();
-          newTab.initialize();
-        } catch (ex) {
-          console.error('Failed to initialize pinned tabs:', ex);
-        }
-      }
-
-      setTimeout(() => {
-        this.#finishedInitializingPins();
-      }, 0);
-
-      gBrowser._updateTabBarForPinnedTabs();
-      gZenUIManager.updateTabsToolbar();
-    }
-
     _onPinnedTabEvent(action, event) {
       if (!this.enabled) return;
       const tab = event.target;
@@ -412,238 +129,22 @@
       }
       switch (action) {
         case 'TabPinned':
-        case 'TabAddedToEssentials':
           tab._zenClickEventListener = this._zenClickEventListener;
           tab.addEventListener('click', tab._zenClickEventListener);
-          this._setPinnedAttributes(tab);
           break;
-        case 'TabRemovedFromEssentials':
-          if (tab.pinned) {
-            this.#onTabMove(tab);
-            break;
-          }
         // [Fall through]
         case 'TabUnpinned':
-          this._removePinnedAttributes(tab);
           if (tab._zenClickEventListener) {
             tab.removeEventListener('click', tab._zenClickEventListener);
             delete tab._zenClickEventListener;
           }
           break;
-        case 'TabMove':
-          this.#onTabMove(tab);
-          break;
-        case 'TabGroupCreate':
-          this.#onTabGroupCreate(event);
-          break;
-        case 'TabGroupRemoved':
-          this.#onTabGroupRemoved(event);
-          break;
-        case 'TabGroupMoved':
-          this.#onTabGroupMoved(event);
-          break;
-        case 'ZenFolderRenamed':
-        case 'ZenFolderIconChanged':
-        case 'TabGroupCollapse':
-        case 'TabGroupExpand':
-        case 'ZenFolderChangedWorkspace':
-          this.#updateGroupInfo(event.originalTarget, action);
-          break;
-        case 'TabGrouped':
-          this.#onTabGrouped(event);
-          break;
-        case 'TabUngrouped':
-          this.#onTabUngrouped(event);
-          break;
         default:
           console.warn('ZenPinnedTabManager: Unhandled tab event', action);
           break;
       }
     }
 
-    async #onTabGroupCreate(event) {
-      const group = event.originalTarget;
-      if (!group.isZenFolder) {
-        return;
-      }
-      if (group.hasAttribute('zen-pin-id')) {
-        return; // Group already exists in storage
-      }
-      const workspaceId = group.getAttribute('zen-workspace-id');
-      let id = await ZenPinnedTabsStorage.createGroup(
-        group.name,
-        group.iconURL,
-        group.collapsed,
-        workspaceId,
-        group.getAttribute('zen-pin-id'),
-        group._pPos
-      );
-      group.setAttribute('zen-pin-id', id);
-      for (const tab of group.tabs) {
-        // Only add it if the tab is directly under the group
-        if (
-          tab.pinned &&
-          tab.hasAttribute('zen-pin-id') &&
-          tab.group === group &&
-          this.hasInitializedPins
-        ) {
-          const tabPinId = tab.getAttribute('zen-pin-id');
-          await ZenPinnedTabsStorage.addTabToGroup(tabPinId, id, /* position */ tab._pPos);
-        }
-      }
-      await this.refreshPinnedTabs();
-    }
-
-    async #onTabGrouped(event) {
-      const tab = event.detail;
-      const group = tab.group;
-      if (!group.isZenFolder) {
-        return;
-      }
-      const pinId = group.getAttribute('zen-pin-id');
-      const tabPinId = tab.getAttribute('zen-pin-id');
-      const tabPin = this._pinsCache?.find((p) => p.uuid === tabPinId);
-      if (!tabPin || !tabPin.group) {
-        return;
-      }
-      ZenPinnedTabsStorage.addTabToGroup(tabPinId, pinId, /* position */ tab._pPos);
-    }
-
-    async #onTabUngrouped(event) {
-      const tab = event.detail;
-      const group = tab.group;
-      if (!group?.isZenFolder) {
-        return;
-      }
-      const tabPinId = tab.getAttribute('zen-pin-id');
-      const tabPin = this._pinsCache?.find((p) => p.uuid === tabPinId);
-      if (!tabPin) {
-        return;
-      }
-      ZenPinnedTabsStorage.removeTabFromGroup(tabPinId, /* position */ tab._pPos);
-    }
-
-    async #updateGroupInfo(group, action) {
-      if (!group?.isZenFolder) {
-        return;
-      }
-      const pinId = group.getAttribute('zen-pin-id');
-      const groupPin = this._pinsCache?.find((p) => p.uuid === pinId);
-      if (groupPin) {
-        groupPin.title = group.name;
-        groupPin.folderIcon = group.iconURL;
-        groupPin.isFolderCollapsed = group.collapsed;
-        groupPin.position = group._pPos;
-        groupPin.parentUuid = group.group?.getAttribute('zen-pin-id') || null;
-        groupPin.workspaceUuid = group.getAttribute('zen-workspace-id') || null;
-        await this.savePin(groupPin);
-        switch (action) {
-          case 'ZenFolderRenamed':
-          case 'ZenFolderIconChanged':
-          case 'TabGroupCollapse':
-          case 'TabGroupExpand':
-            break;
-          default:
-            for (const item of group.allItems) {
-              if (gBrowser.isTabGroup(item)) {
-                await this.#updateGroupInfo(item, action);
-              } else {
-                await this.#onTabMove(item);
-              }
-            }
-        }
-      }
-    }
-
-    async #onTabGroupRemoved(event) {
-      const group = event.originalTarget;
-      if (!group.isZenFolder) {
-        return;
-      }
-      await ZenPinnedTabsStorage.removePin(group.getAttribute('zen-pin-id'));
-      group.removeAttribute('zen-pin-id');
-    }
-
-    async #onTabGroupMoved(event) {
-      const group = event.originalTarget;
-      if (!group.isZenFolder) {
-        return;
-      }
-      const newIndex = group._pPos;
-      const pinId = group.getAttribute('zen-pin-id');
-      if (!pinId) {
-        return;
-      }
-      for (const tab of group.allItemsRecursive) {
-        if (tab.pinned && tab.getAttribute('zen-pin-id') === pinId) {
-          const pin = this._pinsCache.find((p) => p.uuid === pinId);
-          if (pin) {
-            pin.position = tab._pPos;
-            pin.parentUuid = tab.group?.getAttribute('zen-pin-id') || null;
-            pin.workspaceUuid = group.getAttribute('zen-workspace-id');
-            await this.savePin(pin, false);
-          }
-          break;
-        }
-      }
-      const groupPin = this._pinsCache?.find((p) => p.uuid === pinId);
-      if (groupPin) {
-        groupPin.position = newIndex;
-        groupPin.parentUuid = group.group?.getAttribute('zen-pin-id');
-        groupPin.workspaceUuid = group.getAttribute('zen-workspace-id');
-        await this.savePin(groupPin);
-      }
-    }
-
-    async #onTabMove(tab) {
-      if (!tab.pinned || !this._pinsCache) {
-        return;
-      }
-
-      const allTabs = [...gBrowser.tabs, ...gBrowser.tabGroups];
-      for (let i = 0; i < allTabs.length; i++) {
-        const otherTab = allTabs[i];
-        if (
-          otherTab.pinned &&
-          otherTab.getAttribute('zen-pin-id') !== tab.getAttribute('zen-pin-id')
-        ) {
-          const actualPin = this._pinsCache.find(
-            (pin) => pin.uuid === otherTab.getAttribute('zen-pin-id')
-          );
-          if (!actualPin) {
-            continue;
-          }
-          actualPin.position = otherTab._pPos;
-          actualPin.workspaceUuid = otherTab.getAttribute('zen-workspace-id');
-          actualPin.parentUuid = otherTab.group?.getAttribute('zen-pin-id') || null;
-          await this.savePin(actualPin, false);
-        }
-      }
-
-      const actualPin = this._pinsCache.find((pin) => pin.uuid === tab.getAttribute('zen-pin-id'));
-
-      if (!actualPin) {
-        return;
-      }
-      actualPin.position = tab._pPos;
-      actualPin.isEssential = tab.hasAttribute('zen-essential');
-      actualPin.parentUuid = tab.group?.getAttribute('zen-pin-id') || null;
-      actualPin.workspaceUuid = tab.getAttribute('zen-workspace-id') || null;
-
-      // There was a bug where the title and hasStaticLabel attribute were not being set
-      // This is a workaround to fix that
-      if (tab.hasAttribute('zen-has-static-label')) {
-        actualPin.editedTitle = true;
-        actualPin.title = tab.label;
-      }
-      await this.savePin(actualPin);
-      tab.dispatchEvent(
-        new CustomEvent('ZenPinnedTabMoved', {
-          detail: { tab },
-        })
-      );
-    }
-
     async _onTabClick(e) {
       const tab = e.target?.closest('tab');
       if (e.button === 1 && tab) {
@@ -673,106 +174,10 @@
         return;
       }
 
-      const browser = tab.linkedBrowser;
-
-      const pin = this._pinsCache.find((pin) => pin.uuid === tab.getAttribute('zen-pin-id'));
-
-      if (!pin) {
-        return;
-      }
-
-      const userContextId = tab.getAttribute('usercontextid');
-
-      pin.title = tab.label || browser.contentTitle;
-      pin.url = browser.currentURI.spec;
-      pin.workspaceUuid = tab.getAttribute('zen-workspace-id');
-      pin.userContextId = userContextId ? parseInt(userContextId, 10) : 0;
-
-      await this.savePin(pin);
       this.resetPinChangedUrl(tab);
-      await this.refreshPinnedTabs();
       gZenUIManager.showToast('zen-pinned-tab-replaced');
     }
 
-    async _setPinnedAttributes(tab) {
-      if (
-        tab.hasAttribute('zen-pin-id') ||
-        !this._hasFinishedLoading ||
-        tab.hasAttribute('zen-empty-tab')
-      ) {
-        return;
-      }
-
-      this.log(`Setting pinned attributes for tab ${tab.linkedBrowser.currentURI.spec}`);
-      const browser = tab.linkedBrowser;
-
-      const uuid = gZenUIManager.generateUuidv4();
-      const userContextId = tab.getAttribute('usercontextid');
-
-      let entry = null;
-
-      if (tab.getAttribute('zen-pinned-entry')) {
-        entry = JSON.parse(tab.getAttribute('zen-pinned-entry'));
-      }
-
-      await this.savePin({
-        uuid,
-        title: entry?.title || tab.label || browser.contentTitle,
-        url: entry?.url || browser.currentURI.spec,
-        containerTabId: userContextId ? parseInt(userContextId, 10) : 0,
-        workspaceUuid: tab.getAttribute('zen-workspace-id'),
-        isEssential: tab.getAttribute('zen-essential') === 'true',
-        parentUuid: tab.group?.getAttribute('zen-pin-id') || null,
-        position: tab._pPos,
-      });
-
-      tab.setAttribute('zen-pin-id', uuid);
-      tab.dispatchEvent(
-        new CustomEvent('ZenPinnedTabCreated', {
-          detail: { tab },
-        })
-      );
-
-      // This is used while migrating old pins to new system - we don't want to refresh when migrating
-      if (tab.getAttribute('zen-pinned-entry')) {
-        tab.removeAttribute('zen-pinned-entry');
-        return;
-      }
-      this.onLocationChange(browser);
-      await this.refreshPinnedTabs();
-    }
-
-    async _removePinnedAttributes(tab, isClosing = false) {
-      tab.removeAttribute('zen-has-static-label');
-      if (!tab.getAttribute('zen-pin-id') || this._temporarilyUnpiningEssential) {
-        return;
-      }
-
-      if (Services.startup.shuttingDown || window.skipNextCanClose) {
-        return;
-      }
-
-      this.log(`Removing pinned attributes for tab ${tab.getAttribute('zen-pin-id')}`);
-      await ZenPinnedTabsStorage.removePin(tab.getAttribute('zen-pin-id'));
-      this.resetPinChangedUrl(tab);
-
-      if (!isClosing) {
-        tab.removeAttribute('zen-pin-id');
-        tab.removeAttribute('zen-essential'); // Just in case
-
-        if (!tab.hasAttribute('zen-workspace-id') && gZenWorkspaces.workspaceEnabled) {
-          const workspace = await gZenWorkspaces.getActiveWorkspace();
-          tab.setAttribute('zen-workspace-id', workspace.uuid);
-        }
-      }
-      await this.refreshPinnedTabs();
-      tab.dispatchEvent(
-        new CustomEvent('ZenPinnedTabRemoved', {
-          detail: { tab },
-        })
-      );
-    }
-
     _initClosePinnedTabShortcut() {
       let cmdClose = document.getElementById('cmd_close');
 
@@ -781,21 +186,6 @@
       }
     }
 
-    async savePin(pin, notifyObservers = true) {
-      if (!this.hasInitializedPins && !gZenUIManager.testingEnabled) {
-        return;
-      }
-      const existingPin = this._pinsCache.find((p) => p.uuid === pin.uuid);
-      if (existingPin) {
-        Object.assign(existingPin, pin);
-      } else {
-        // We shouldn't need it, but just in case there's
-        // a race condition while making new pinned tabs.
-        this._pinsCache.push(pin);
-      }
-      await ZenPinnedTabsStorage.savePin(pin, notifyObservers);
-    }
-
     async onCloseTabShortcut(
       event,
       selectedTab = gBrowser.selectedTab,
@@ -842,7 +232,6 @@
         switch (behavior) {
           case 'close': {
             for (const tab of pinnedTabs) {
-              this._removePinnedAttributes(tab, true);
               gBrowser.removeTab(tab, { animate: true });
             }
             break;
@@ -1018,12 +407,6 @@
           tab.removeAttribute('zen-workspace-id');
         }
         if (tab.pinned && tab.hasAttribute('zen-pin-id')) {
-          const pin = this._pinsCache.find((pin) => pin.uuid === tab.getAttribute('zen-pin-id'));
-          if (pin) {
-            pin.isEssential = true;
-            pin.workspaceUuid = null;
-            this.savePin(pin);
-          }
           gBrowser.zenHandleTabMove(tab, () => {
             if (tab.ownerGlobal !== window) {
               tab = gBrowser.adoptTab(tab, {
@@ -1414,11 +797,8 @@
       return document.documentElement.getAttribute('zen-sidebar-expanded') === 'true';
     }
 
-    async updatePinTitle(tab, newTitle, isEdited = true, notifyObservers = true) {
+    async updatePinTitle(tab, newTitle, isEdited = true) {
       const uuid = tab.getAttribute('zen-pin-id');
-      await ZenPinnedTabsStorage.updatePinTitle(uuid, newTitle, isEdited, notifyObservers);
-
-      await this.refreshPinnedTabs();
 
       const browsers = Services.wm.getEnumerator('navigator:browser');
 
@@ -1563,6 +943,7 @@
     }
 
     async onTabLabelChanged(tab) {
+      tab.dispatchEvent(new CustomEvent('ZenTabLabelChanged', { detail: { tab } }));
       if (!this._pinsCache) {
         return;
       }

src/zen/workspaces/ZenWindowSyncing.mjs

@@ -0,0 +1,308 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+{
+  class nsZenWorkspaceWindowSync extends nsZenMultiWindowFeature {
+    #ignoreNextEvents = false;
+    #waitForPromise = null;
+
+    constructor() {
+      super();
+      if (!window.closed) {
+        this.init();
+      }
+    }
+
+    async init() {
+      await gZenWorkspaces.promiseInitialized;
+      this.#makeSureAllTabsHaveIds();
+      this.#setUpEventListeners();
+    }
+
+    #makeSureAllTabsHaveIds() {
+      const allTabs = gZenWorkspaces.allStoredTabs;
+      for (const tab of allTabs) {
+        if (!tab.hasAttribute('zen-sync-id') && !tab.hasAttribute('zen-empty-tab')) {
+          const tabId = gZenUIManager.generateUuidv4();
+          tab.setAttribute('zen-sync-id', tabId);
+        }
+      }
+    }
+
+    #setUpEventListeners() {
+      const kEvents = [
+        'TabClose',
+        'TabOpen',
+        'TabMove',
+
+        'TabPinned',
+        'TabUnpinned',
+
+        'TabAddedToEssentials',
+        'TabRemovedFromEssentials',
+
+        'TabHide',
+        'TabShow',
+
+        'ZenTabIconChanged',
+        'ZenTabLabelChanged',
+
+        'TabGroupCreate',
+        'TabGroupRemoved',
+        'TabGrouped',
+        'TabUngrouped',
+        'TabGroupMoved',
+      ];
+      const eventListener = this.#handleEvent.bind(this);
+      for (const event of kEvents) {
+        window.addEventListener(event, eventListener);
+      }
+
+      window.addEventListener('unload', () => {
+        for (const event of kEvents) {
+          window.removeEventListener(event, eventListener);
+        }
+      });
+    }
+
+    #handleEvent(event) {
+      this.#propagateToOtherWindows(event);
+    }
+
+    async #propagateToOtherWindows(event) {
+      if (this.#ignoreNextEvents) {
+        return;
+      }
+      if (this.#waitForPromise) {
+        await this.#waitForPromise;
+      }
+      this.#waitForPromise = new Promise((resolve) => {
+        this.foreachWindowAsActive(async (browser) => {
+          if (browser.gZenWorkspaceWindowSync && !this.windowIsActive(browser)) {
+            await browser.gZenWorkspaceWindowSync.onExternalTabEvent(event);
+          }
+        }).then(() => {
+          resolve();
+        });
+      });
+    }
+
+    async onExternalTabEvent(event) {
+      this.#ignoreNextEvents = true;
+      switch (event.type) {
+        case 'TabClose':
+          this.#onTabClose(event);
+          break;
+        case 'TabOpen':
+          await this.#onTabOpen(event);
+          break;
+        case 'TabPinned':
+          this.#onTabPinned(event);
+          break;
+        case 'TabUnpinned':
+          this.#onTabUnpinned(event);
+          break;
+        case 'TabAddedToEssentials':
+          this.#onTabAddedToEssentials(event);
+          break;
+        case 'TabRemovedFromEssentials':
+          this.#onTabRemovedFromEssentials(event);
+          break;
+        case 'TabHide':
+          this.#onTabHide(event);
+          break;
+        case 'TabShow':
+          this.#onTabShow(event);
+          break;
+        case 'TabMove':
+        case 'TabGroupMoved':
+          this.#onTabMove(event);
+          break;
+        case 'ZenTabIconChanged':
+          this.#onTabIconChanged(event);
+          break;
+        case 'ZenTabLabelChanged':
+          this.#onTabLabelChanged(event);
+          break;
+        case 'TabGroupCreate':
+          this.#onTabGroupCreate(event);
+          break;
+        case 'TabGroupRemoved':
+        case 'TabGrouped':
+        case 'TabUngrouped':
+          // Tab grouping changes are automatically synced by Firefox
+          break;
+        default:
+          console.warn(`Unhandled event type: ${event.type}`);
+          break;
+      }
+      this.#ignoreNextEvents = false;
+    }
+
+    #getTabId(tab) {
+      return tab.getAttribute('zen-sync-id');
+    }
+
+    #getTabWithId(tabId) {
+      for (const tab of gZenWorkspaces.allStoredTabs) {
+        if (this.#getTabId(tab) === tabId) {
+          return tab;
+        }
+      }
+      return null;
+    }
+
+    #onTabClose(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToClose = this.#getTabWithId(tabId);
+      if (tabToClose) {
+        gBrowser.removeTab(tabToClose);
+      }
+    }
+
+    #onTabPinned(event) {
+      const targetTab = event.target;
+      if (targetTab.hasAttribute('zen-essential')) {
+        return this.#onTabAddedToEssentials(event);
+      }
+      const tabId = this.#getTabId(targetTab);
+      const elementIndex = targetTab.elementIndex;
+      const tabToPin = this.#getTabWithId(tabId);
+      if (tabToPin) {
+        gBrowser.pinTab(tabToPin);
+        gBrowser.moveTabTo(tabToPin, { elementIndex, forceUngrouped: !!targetTab.group });
+      }
+    }
+
+    #onTabUnpinned(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToUnpin = this.#getTabWithId(tabId);
+      if (tabToUnpin) {
+        gBrowser.unpinTab(tabToUnpin);
+      }
+    }
+
+    #onTabIconChanged(event) {
+      this.#updateTabIconAndLabel(event);
+    }
+
+    #onTabLabelChanged(event) {
+      this.#updateTabIconAndLabel(event);
+    }
+
+    #updateTabIconAndLabel(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToChange = this.#getTabWithId(tabId);
+      if (tabToChange && tabToChange.hasAttribute('pending')) {
+        gBrowser.setIcon(tabToChange, gBrowser.getIcon(targetTab));
+        gBrowser._setTabLabel(tabToChange, targetTab.label);
+      }
+    }
+
+    #onTabAddedToEssentials(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToAdd = this.#getTabWithId(tabId);
+      if (tabToAdd) {
+        gZenPinnedTabManager.addToEssentials(tabToAdd);
+      }
+    }
+
+    #onTabRemovedFromEssentials(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToRemove = this.#getTabWithId(tabId);
+      if (tabToRemove) {
+        gZenPinnedTabManager.removeFromEssentials(tabToRemove);
+      }
+    }
+
+    #onTabHide(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToHide = this.#getTabWithId(tabId);
+      if (tabToHide) {
+        gBrowser.hideTab(tabToHide);
+      }
+    }
+
+    #onTabShow(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToShow = this.#getTabWithId(tabId);
+      if (tabToShow) {
+        gBrowser.showTab(tabToShow);
+      }
+    }
+
+    #onTabMove(event) {
+      const targetTab = event.target;
+      const tabId = this.#getTabId(targetTab);
+      const tabToMove = this.#getTabWithId(tabId);
+      const workspaceId = targetTab.getAttribute('zen-workspace-id');
+      const isEssential = targetTab.hasAttribute('zen-essential');
+      if (tabToMove) {
+        let tabSibling = targetTab.previousElementSibling;
+        let isFirst = false;
+        if (!tabSibling?.hasAttribute('zen-sync-id')) {
+          isFirst = true;
+        }
+        gBrowser.zenHandleTabMove(tabToMove, () => {
+          if (isFirst) {
+            let container;
+            if (isEssential) {
+              container = gZenWorkspaces.getEssentialsSection(tabToMove);
+            } else {
+              const workspaceElement = gZenWorkspaces.workspaceElement(workspaceId);
+              container = tabToMove.pinned
+                ? workspaceElement.pinnedTabsContainer
+                : workspaceElement.tabsContainer;
+            }
+            container.insertBefore(tabToMove, container.firstChild);
+          } else {
+            let relativeTab = gZenWorkspaces.allStoredTabs.find((tab) => {
+              return this.#getTabId(tab) === this.#getTabId(tabSibling);
+            });
+            if (relativeTab) {
+              relativeTab.after(tabToMove);
+            }
+          }
+        });
+      }
+    }
+
+    async #onTabOpen(event) {
+      const targetTab = event.target;
+      const isPinned = targetTab.pinned;
+      const isEssential = isPinned && targetTab.hasAttribute('zen-essential');
+      if (!this.#getTabId(targetTab) && !targetTab.hasAttribute('zen-empty-tab')) {
+        const tabId = gZenUIManager.generateUuidv4();
+        targetTab.setAttribute('zen-sync-id', tabId);
+      }
+      const duplicatedTab = gBrowser.addTrustedTab(targetTab.linkedBrowser.currentURI.spec, {
+        createLazyBrowser: true,
+        essential: isEssential,
+        pinned: isPinned,
+      });
+      if (!isEssential) {
+        gZenWorkspaces.moveTabToWorkspace(
+          duplicatedTab,
+          targetTab.getAttribute('zen-workspace-id')
+        );
+      }
+      duplicatedTab.setAttribute('zen-sync-id', targetTab.getAttribute('zen-sync-id'));
+    }
+
+    #onTabGroupCreate(event) {
+      void event;
+      //const targetGroup = event.target;
+      //const isSplitView = targetGroup.classList.contains('zen-split-view');
+      //const isFolder = targetGroup.isZenFolder;
+    }
+  }
+
+  window.gZenWorkspaceWindowSync = new nsZenWorkspaceWindowSync();
+}

src/zen/workspaces/ZenWorkspaces.mjs

@@ -932,7 +932,6 @@ var gZenWorkspaces = new (class extends nsZenMultiWindowFeature {
     await this.workspaceBookmarks();
     await this.initializeTabsStripSections();
     this._initializeEmptyTab();
-    await gZenPinnedTabManager.refreshPinnedTabs({ init: true });
     await this.changeWorkspace(activeWorkspace, { onInit: true });
     this.#fixTabPositions();
     this.onWindowResize();
@@ -1471,11 +1470,6 @@ var gZenWorkspaces = new (class extends nsZenMultiWindowFeature {
         !tab.hasAttribute('zen-empty-tab') &&
         !tab.hasAttribute('zen-essential')
     );
-    for (const tab of tabs) {
-      if (tab.pinned) {
-        await ZenPinnedTabsStorage.removePin(tab.getAttribute('zen-pin-id'));
-      }
-    }
     gBrowser.removeTabs(tabs, {
       animate: false,
       skipSessionStore: true,

src/zen/zen.globals.js

@@ -28,7 +28,6 @@ export default [
   'ZenWorkspaceBookmarksStorage',
 
   'gZenPinnedTabManager',
-  'ZenPinnedTabsStorage',
 
   'gZenEmojiPicker',
   'gZenSessionStore',