gh-14830: Fixed dragging on text makes the entire window to move (gh-14833)

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

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 `153.0`! 🚀
-- [`Twilight`](https://zen-browser.app/download?twilight) - Is currently built using Firefox version `RC 153.0`!
+- [`Release`](https://zen-browser.app/download) - Is currently built using Firefox version `153.0.1`! 🚀
+- [`Twilight`](https://zen-browser.app/download?twilight) - Is currently built using Firefox version `RC 153.0.1`!
 
 ### Contributing
 

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

@@ -1 +1 @@
-b1d3fe8f65751e6d695fa9ef94b11ad81e70dac1
+30959a45eaaf0bc499f3054793c76c6d7f0c8bc2

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

@@ -283,7 +283,8 @@ zen-page-info-shortcut = View Page Info
 zen-find-shortcut = Find on Page
 zen-search-find-again-shortcut = Find Again
 zen-search-find-again-shortcut-prev = Find Previous
-zen-search-find-again-shortcut-2 = Find Again (Alt)
+zen-search-find-again-shortcut-alt = Find Again (Alt)
+zen-search-find-again-shortcut-prev-alt = Find Previous (Alt)
 zen-bookmark-this-page-shortcut = Bookmark This Page
 zen-bookmark-show-library-shortcut = Show Bookmarks Library
 zen-key-stop = Stop Loading

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

@@ -82,6 +82,7 @@ zen-workspace-creation-profile = Profile
     .tooltiptext = Profiles are used to separate cookies and site data between spaces.
 zen-workspace-creation-header = Create a Space
 zen-workspace-creation-label = Spaces are used to organize your tabs and sessions.
+zen-workspace-default-profile = Default
 
 zen-workspaces-delete-workspace-title = Delete Space?
 zen-workspaces-delete-workspace-body = Are you sure you want to delete { $name }? This action cannot be undone.

prefs/zen/compact-mode.yaml

@@ -20,6 +20,14 @@
 - name: zen.view.compact.sidebar-keep-hover.duration
   value: 150
 
+# How far (in CSS pixels) the mouse may travel past the window bounds after
+# leaving the window before the hovered sidebar/toolbar is collapsed
+- name: zen.view.compact.outside-window-edge-offset.horizontal
+  value: 200
+
+- name: zen.view.compact.outside-window-edge-offset.vertical
+  value: 100
+
 - name: zen.view.compact.animate-sidebar
   value: true
 

prefs/zen/view.yaml

@@ -46,6 +46,12 @@
 - name: zen.view.context-menu.refresh
   value: "@IS_TWILIGHT@"
 
+- name: zen.view.drag-window-from-content
+  value: true
+
+- name: zen.view.drag-window-from-content.height-percentage
+  value: 10
+
 - name: zen.view.borderless-fullscreen
   value: true
 

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

@@ -803,6 +803,7 @@ const zenMissingKeyboardShortcutL10n = {
 
   key_inspectorMac: "zen-key-inspector-mac",
   key_findSelection: "zen-key-find-selection",
+  key_findPrevious2: "zen-search-find-again-shortcut-prev-alt",
 
   // Devtools
   key_toggleToolbox: "zen-devtools-toggle-shortcut",
@@ -826,6 +827,9 @@ var zenIgnoreKeyboardShortcutIDs = [
   "key_exitFullScreen_old",
   "key_exitFullScreen_compat",
   "key_duplicateTab",
+  "key_addTabSplitView",
+  "key_separateTabSplitView",
+  "viewOpenTabsSidebarKb",
 ];
 
 var zenIgnoreKeyboardShortcutL10n = [

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

@@ -236,7 +236,7 @@ index c42b1a1a8df6b38886c17f71ea88e5aaa7eebc80..c741404ed973ee3ac246fe246c0f645e
        }
  
 -      if (replace) {
-+      if (replace && !(!targetTab && this.selectedTab?.hasAttribute('zen-empty-tab'))) {
++      if (replace && !((targetTab || this.selectedTab)?.hasAttribute('zen-empty-tab'))) {
          if (this.isTabGroupLabel(targetTab)) {
            throw new Error(
              "Replacing a tab group label with a tab is not supported"

src/browser/themes/shared/places/organizer-shared-css.patch

@@ -0,0 +1,21 @@
+diff --git a/browser/themes/shared/places/organizer-shared.css b/browser/themes/shared/places/organizer-shared.css
+index fe6b79cfc2453927c324a044bd62040f866def95..a93813c76ba3633c365a739289b39187c0d1e881 100644
+--- a/browser/themes/shared/places/organizer-shared.css
++++ b/browser/themes/shared/places/organizer-shared.css
+@@ -52,6 +52,16 @@
+   }
+ }
+ 
++#places .zenEditBMPanel_fieldContainer {
++  display: contents;
++}
++
++#places label[control="editBMPanel_workspacesSelectorExpander"],
++#places #editBMPanel_workspaceDropdown,
++#places #editBMPanel_workspaceList {
++  display: none;
++}
++
+ #editBMPanel_itemsCountText {
+   grid-column: auto / span 2;
+   justify-self: center;

src/dom/base/Document-cpp.patch

@@ -1,8 +1,8 @@
 diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
-index 328b7524810322561700347fa7f26403897635a8..58d33d68e050d11ea712413ad5c2170a112e404a 100644
+index 73eb08f648d55121a0cd96cd808f932fb14bfee6..efa99861a5da12ad8d0daa2c0eb1473c57810397 100644
 --- a/dom/base/Document.cpp
 +++ b/dom/base/Document.cpp
-@@ -467,6 +467,7 @@
+@@ -471,6 +471,7 @@
  #include "prtime.h"
  #include "prtypes.h"
  #include "xpcpublic.h"
@@ -10,14 +10,15 @@ index 328b7524810322561700347fa7f26403897635a8..58d33d68e050d11ea712413ad5c2170a
  
  // clang-format off
  #include "mozilla/Encoding.h"
-@@ -3198,6 +3199,10 @@ void Document::FillStyleSetUserAndUASheets() {
-   for (StyleSheet* sheet : *sheetService->UserStyleSheets()) {
-     styleSet.AppendStyleSheet(*sheet);
-   }
-+  if (auto sheet = zen::ZenStyleSheetCache::Singleton()->GetModsSheet(); sheet && IsInChromeDocShell()) {
-+    // The mods sheet is only used in the chrome docshell.
-+    styleSet.AppendStyleSheet(*sheet);
-+  }
+@@ -3164,6 +3165,11 @@ void Document::FillStyleSetUserAndUASheets() {
+     }
+   };
  
-   StyleSheet* sheet = IsInChromeDocShell() ? cache->GetUserChromeSheet()
-                                            : cache->GetUserContentSheet();
++  if (IsInChromeDocShell()) {
++    // The mods sheet is only used in the chrome docshell.
++    MaybeAppend(zen::ZenStyleSheetCache::Singleton()->GetModsSheet());
++  }
++
+   MaybeAppend(IsInChromeDocShell() ? cache->GetUserChromeSheet()
+                                    : cache->GetUserContentSheet());
+   MaybeAppend(cache->GetUASheet());

src/toolkit/mozapps/extensions/Blocklist-sys-mjs.patch

@@ -0,0 +1,22 @@
+diff --git a/toolkit/mozapps/extensions/Blocklist.sys.mjs b/toolkit/mozapps/extensions/Blocklist.sys.mjs
+index 4e1e0aac91612c846bb664efe3dbb50ecf63597d..93eb9a05520198eb3f9af35aa58d789719169434 100644
+--- a/toolkit/mozapps/extensions/Blocklist.sys.mjs
++++ b/toolkit/mozapps/extensions/Blocklist.sys.mjs
+@@ -411,7 +411,7 @@ class TargetAppFilter {
+     if (!Array.isArray(versionRange)) {
+       const { maxVersion = "*" } = versionRange;
+       const matchesRange =
+-        Services.vc.compare(lazy.gApp.version, maxVersion) <= 0;
++        Services.vc.compare(AppConstants.ZEN_FIREFOX_VERSION, maxVersion) <= 0;
+       return matchesRange ? entry : null;
+     }
+ 
+@@ -433,7 +433,7 @@ class TargetAppFilter {
+         const { maxVersion = "*" } = ta;
+         if (
+           guid == lazy.gAppID &&
+-          Services.vc.compare(lazy.gApp.version, maxVersion) <= 0
++          Services.vc.compare(AppConstants.ZEN_FIREFOX_VERSION, maxVersion) <= 0
+         ) {
+           return entry;
+         }

src/zen/boosts/ZenBoostsEditor.mjs

@@ -64,11 +64,11 @@ export class nsZenBoostEditor {
   }
 
   /**
-   * Returns the ZenBoosts JSWindowActor child for the currently selected tab.
+   * Returns the parent Boost JSActor for the currently selected tab.
    *
-   * @returns {ZenBoostsChild} zenBoostsChild Boost JSActor child
+   * @returns {ZenBoostsParent} Boost JSActor parent
    */
-  get zenBoostsChild() {
+  get zenBoostsParent() {
     const linkedBrowser = this.openerWindow.gBrowser.selectedTab.linkedBrowser;
     const actor =
       linkedBrowser.browsingContext.currentWindowGlobal.getActor("ZenBoosts");
@@ -466,13 +466,13 @@ export class nsZenBoostEditor {
   }
 
   async onZapButtonPressed() {
-    this.zenBoostsChild.sendQuery("ZenBoost:ToggleZapMode");
+    this.zenBoostsParent.sendQuery("ZenBoost:ToggleZapMode");
     // Focus the parent browser window
     this.openerWindow.focus();
   }
 
   async onPickerButtonPressed() {
-    this.zenBoostsChild.sendQuery("ZenBoost:TogglePickerMode");
+    this.zenBoostsParent.sendQuery("ZenBoost:TogglePickerMode");
     this.openerWindow.focus();
   }
 
@@ -497,11 +497,11 @@ ${cssSelector} {
   }
 
   onInspectorButtonPressed() {
-    this.zenBoostsChild.sendQuery("ZenBoost:OpenInspector");
+    this.zenBoostsParent.sendQuery("ZenBoost:OpenInspector");
   }
 
   async onUpdateZapButtonVisual() {
-    const actor = this.zenBoostsChild;
+    const actor = this.zenBoostsParent;
     const zapButton = this.doc.getElementById("zen-boost-zap");
 
     const zapEnabled = await actor.sendQuery("ZenBoost:ZapModeEnabled");
@@ -513,7 +513,7 @@ ${cssSelector} {
 
   async onUpdatePickerButtonVisual() {
     const pickerButton = this.doc.getElementById("zen-boost-css-picker");
-    const selectEnabled = await this.zenBoostsChild.sendQuery(
+    const selectEnabled = await this.zenBoostsParent.sendQuery(
       "ZenBoost:SelectorPickerModeEnabled"
     );
 
@@ -660,7 +660,7 @@ ${cssSelector} {
   /**
    * Handles the size toggle button press, cycling through size override options
    */
-  async onBoostSizePressed() {
+  onBoostSizePressed() {
     if (this.currentBoostData.sizeOverride == 1) {
       this.currentBoostData.sizeOverride = 1.1;
     } else if (this.currentBoostData.sizeOverride == 1.1) {
@@ -671,7 +671,7 @@ ${cssSelector} {
       this.currentBoostData.sizeOverride = 0.9;
     } else if (this.currentBoostData.sizeOverride == 0.9) {
       this.currentBoostData.sizeOverride = 1;
-      await this.zenBoostsChild.updateBoostSizeOverride(
+      this.zenBoostsParent.updateBoostSizeOverride(
         this.currentBoostData.sizeOverride,
         /* disable: */ true
       );

src/zen/boosts/actors/ZenBoostsParent.sys.mjs

@@ -85,7 +85,7 @@ export class ZenBoostsParent extends JSWindowActorParent {
       (sizeOverride !== 1 || disable)
     ) {
       const fullZoom = this.browsingContext.topChromeWindow.FullZoom;
-      fullZoom.setZoom(sizeOverride);
+      fullZoom.setZoom(sizeOverride, this.browsingContext.top.embedderElement);
     }
   }
 

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

@@ -353,3 +353,11 @@ body,
 :root[zen-right-side="true"] #zen-appcontent-navbar-wrapper #PanelUI-button {
   order: 2;
 }
+
+/* See #14409: firefox 150's body paint containment prevents the right side compact
+ sidebar from remaining active at the screen edge in macOS fullscreen */
+@media (-moz-platform: macos) {
+  :root[macOSNativeFullscreen][zen-compact-mode][zen-right-side] body {
+    contain: none;
+  }
+}

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

@@ -712,7 +712,7 @@
 }
 
 /* Hide the results body when there are no results, to avoid showing an empty box */
-.urlbarView[noresults] > .urlbarView-body-outer > .urlbarView-body-inner,
+.urlbar[noresults] .urlbarView > .urlbarView-body-outer > .urlbarView-body-inner,
 #urlbar-search-mode-indicator-close {
   display: none;
 }

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

@@ -190,7 +190,7 @@
   --urlbar-box-active-bgcolor: var(--toolbarbutton-hover-background) !important;
   --zen-input-border-color: light-dark(rgb(204, 204, 204), rgb(66, 65, 77));
   --urlbar-box-hover-bgcolor: var(--toolbarbutton-hover-background) !important;
-  --input-bgcolor: light-dark(rgba(255, 255, 255, 0.2), rgba(0, 0, 0, 0.2)) !important;
+  --input-text-background-color: light-dark(rgba(255, 255, 255, 0.2), rgba(0, 0, 0, 0.2)) !important;
   --toolbar-field-focus-background-color: light-dark(
     rgba(255, 255, 255, 0.25),
     rgba(0, 0, 0, 0.3)

src/zen/common/sys/ZenActorsManager.sys.mjs

@@ -57,6 +57,22 @@ let JSWINDOWACTORS = {
     remoteTypes: ["web", "file"],
     enablePreference: "zen.glance.enabled",
   },
+  ZenWindowDrag: {
+    parent: {
+      esModuleURI: "resource:///actors/ZenWindowDragParent.sys.mjs",
+    },
+    child: {
+      esModuleURI: "resource:///actors/ZenWindowDragChild.sys.mjs",
+      events: {
+        mousedown: {
+          mozSystemGroup: true,
+        },
+      },
+    },
+    messageManagerGroups: ["browsers"],
+    remoteTypes: ["web", "file"],
+    enablePreference: "zen.view.drag-window-from-content",
+  },
 };
 
 if (!Services.appinfo.inSafeMode) {

src/zen/compact-mode/ZenCompactMode.mjs

@@ -34,6 +34,29 @@ XPCOMUtils.defineLazyPreferenceGetter(
   true
 );
 
+// Distance (in CSS pixels) the mouse can travel past the window bounds after
+// leaving the window before the hovered element is collapsed
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "COMPACT_MODE_OUTSIDE_WINDOW_HORIZONTAL_OFFSET",
+  "zen.view.compact.outside-window-edge-offset.horizontal",
+  250
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "COMPACT_MODE_OUTSIDE_WINDOW_VERTICAL_OFFSET",
+  "zen.view.compact.outside-window-edge-offset.vertical",
+  150
+);
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "zenMouseTracker",
+  "@mozilla.org/zen/mouse-tracker;1",
+  Ci.nsIZenMouseTracker
+);
+
 ChromeUtils.defineLazyGetter(lazy, "mainAppWrapper", () =>
   document.getElementById("zen-main-app-wrapper")
 );
@@ -71,9 +94,21 @@ window.gZenCompactModeManager = {
       tabIsRightObserver
     );
 
+    const outsideMouseTrackerExitObserver =
+      this._onOutsideMouseTrackerExit.bind(this);
+    Services.obs.addObserver(
+      outsideMouseTrackerExitObserver,
+      "zen-mouse-tracker:exited"
+    );
+
     window.addEventListener(
       "unload",
       () => {
+        this._stopTrackingMouseOutsideWindow();
+        Services.obs.removeObserver(
+          outsideMouseTrackerExitObserver,
+          "zen-mouse-tracker:exited"
+        );
         Services.prefs.removeObserver(
           "zen.tabs.vertical.right-side",
           tabIsRightObserver
@@ -94,6 +129,10 @@ window.gZenCompactModeManager = {
       this._clearAllHoverStates()
     );
 
+    // Hide any element kept open by the outside mouse tracking as soon as the
+    // window loses focus
+    window.addEventListener("deactivate", () => this._collapseTrackedElement());
+
     this._canShowBackgroundTabToast = Services.prefs.getBoolPref(
       "zen.view.compact.show-background-tab-toast",
       true
@@ -149,6 +188,7 @@ window.gZenCompactModeManager = {
       return;
     }
     delete this._isTabBeingDragged;
+    this._stopTrackingMouseOutsideWindow();
     this.sidebar.removeAttribute("zen-user-show");
     // We use this element in order to make it persis across restarts, by using the XULStore.
     // main-window can't store attributes other than window sizes, so we use this instead
@@ -723,6 +763,9 @@ window.gZenCompactModeManager = {
       }
     } else {
       if (attr === "zen-has-hover") {
+        if (element === this._outsideTrackedElement) {
+          this._stopTrackingMouseOutsideWindow();
+        }
         element.removeAttribute("zen-has-implicit-hover");
         gURLBar.updateTextOverflow();
       }
@@ -886,18 +929,23 @@ window.gZenCompactModeManager = {
           }
           window.cancelAnimationFrame(this._removeHoverFrames[target.id]);
 
-          this.flashElement(
-            target,
-            this.hideAfterHoverDuration,
-            "has-hover" + target.id,
-            "zen-has-hover"
-          );
+          if (!this._trackMouseOutsideWindow(entry.screenEdge, target)) {
+            // We can't track the mouse position outside of the window on
+            // this platform, fall back to hiding after a fixed duration
+            this.flashElement(
+              target,
+              this.hideAfterHoverDuration,
+              "has-hover" + target.id,
+              "zen-has-hover"
+            );
+          }
           document.addEventListener(
             "mousemove",
             () => {
               if (target.matches(":hover")) {
                 return;
               }
+              // Closing the element also stops the outside mouse tracking
               this._setElementExpandAttribute(target, false);
               this.clearFlashTimeout("has-hover" + target.id);
             },
@@ -941,7 +989,55 @@ window.gZenCompactModeManager = {
     return bBox.left - error < x && x < bBox.right + error;
   },
 
+  _trackMouseOutsideWindow(screenEdge, target) {
+    this._stopTrackingMouseOutsideWindow();
+    const maxEdgeOffset =
+      screenEdge === "left" || screenEdge === "right"
+        ? lazy.COMPACT_MODE_OUTSIDE_WINDOW_HORIZONTAL_OFFSET
+        : lazy.COMPACT_MODE_OUTSIDE_WINDOW_VERTICAL_OFFSET;
+    try {
+      lazy.zenMouseTracker.registerWindow(window, screenEdge, maxEdgeOffset);
+    } catch (e) {
+      // The platform can't track the global mouse position (e.g. Linux)
+      return false;
+    }
+    this._outsideTrackedElement = target;
+    this.clearFlashTimeout("has-hover" + target.id);
+    window.requestAnimationFrame(() => {
+      if (this._outsideTrackedElement === target) {
+        this._setElementExpandAttribute(target, true);
+      }
+    });
+    return true;
+  },
+
+  _stopTrackingMouseOutsideWindow() {
+    const target = this._outsideTrackedElement;
+    if (!target) {
+      return;
+    }
+    this._outsideTrackedElement = null;
+    lazy.zenMouseTracker.unregisterWindow(window);
+  },
+
+  _collapseTrackedElement() {
+    const target = this._outsideTrackedElement;
+    if (!target) {
+      return;
+    }
+    // Closing the element also unregisters us from the mouse tracker
+    this._setElementExpandAttribute(target, false);
+    this.clearFlashTimeout("has-hover" + target.id);
+  },
+
+  _onOutsideMouseTrackerExit(subject) {
+    if (subject === window) {
+      this._collapseTrackedElement();
+    }
+  },
+
   _clearAllHoverStates() {
+    this._stopTrackingMouseOutsideWindow();
     // Clear hover attributes from all hoverable elements
     for (let entry of this.hoverableElements) {
       const target = entry.element;
@@ -977,6 +1073,14 @@ window.gZenCompactModeManager = {
       !gZenGlanceManager._animating &&
       !this._nextTimeWillBeActive
     ) {
+      const isTabRoutedToCurrentSpace =
+        beforeRouteResult.targetRoute === gZenWorkspaces.activeWorkspace;
+      // Do not show the toast if the sidebar is not hidden and
+      // the tab is being routed to the current space
+      if (!isSidebarHidden && isTabRoutedToCurrentSpace) {
+        return;
+      }
+
       let messageId = "zen-background-tab-opened-toast";
       let toastOptions = {
         button: {
@@ -988,7 +1092,7 @@ window.gZenCompactModeManager = {
         },
       };
 
-      if (beforeRouteResult.isRouteFound) {
+      if (beforeRouteResult.isRouteFound && !isTabRoutedToCurrentSpace) {
         messageId = "zen-space-routing-tab-routed-toast";
         toastOptions = {
           l10nArgs: { targetWorkspace: beforeRouteResult.targetWorkspaceName },

src/zen/compact-mode/ZenMouseTracker.cpp

@@ -0,0 +1,246 @@
+/* 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/. */
+
+#include "ZenMouseTracker.h"
+#include "ZenMouseTrackerInternal.h"
+
+#include <atomic>
+
+#include "mozilla/Services.h"
+#include "mozilla/WidgetUtils.h"
+#include "nsIObserverService.h"
+#include "nsIWidget.h"
+#include "nsThreadUtils.h"
+
+namespace zen {
+
+NS_IMPL_ISUPPORTS(ZenMouseTracker, nsIZenMouseTracker, nsIObserver)
+
+static ZenMouseTracker* sInstance = nullptr;
+
+// Pointer moves are coalesced: the backends may report them faster than we
+// want to run the checks, and on Windows they arrive from a low level hook
+// where as little work as possible should happen. These are atomic since
+// some backends (e.g. the macOS global event monitor) may deliver the moves
+// off the main thread.
+static std::atomic<int32_t> sLatestPointerX{0};
+static std::atomic<int32_t> sLatestPointerY{0};
+static std::atomic<bool> sPendingEvaluation{false};
+
+ZenMouseTracker::ZenMouseTracker() {
+  MOZ_ASSERT(NS_IsMainThread());
+  sInstance = this;
+}
+
+ZenMouseTracker::~ZenMouseTracker() {
+  ZenNativeMouseMonitor::Stop();
+  if (sInstance == this) {
+    sInstance = nullptr;
+  }
+}
+
+// static
+mozilla::Maybe<ZenMouseTracker::TrackedEdge> ZenMouseTracker::ParseEdge(
+    const nsACString& aScreenEdge) {
+  if (aScreenEdge.EqualsLiteral("left")) {
+    return mozilla::Some(TrackedEdge::Left);
+  }
+  if (aScreenEdge.EqualsLiteral("right")) {
+    return mozilla::Some(TrackedEdge::Right);
+  }
+  if (aScreenEdge.EqualsLiteral("top")) {
+    return mozilla::Some(TrackedEdge::Top);
+  }
+  if (aScreenEdge.EqualsLiteral("bottom")) {
+    return mozilla::Some(TrackedEdge::Bottom);
+  }
+  return mozilla::Nothing();
+}
+
+NS_IMETHODIMP
+ZenMouseTracker::RegisterWindow(mozIDOMWindowProxy* aWindow,
+                                const nsACString& aScreenEdge,
+                                float aMaxEdgeOffset) {
+  MOZ_ASSERT(NS_IsMainThread());
+  const auto edge = ParseEdge(aScreenEdge);
+  if (!aWindow || edge.isNothing() || aMaxEdgeOffset < 0.0f) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);
+  if (!window) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsresult rv = ZenNativeMouseMonitor::Start();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  for (auto& tracked : mTracked) {
+    if (tracked.mWindow == window) {
+      tracked.mEdge = *edge;
+      tracked.mMaxEdgeOffset = aMaxEdgeOffset;
+      return NS_OK;
+    }
+  }
+  mTracked.AppendElement(TrackedWindow{window, *edge, aMaxEdgeOffset});
+  AddObservers();
+  return NS_OK;
+}
+
+void ZenMouseTracker::AddObservers() {
+  if (mObserving) {
+    return;
+  }
+  if (nsCOMPtr<nsIObserverService> obs =
+          mozilla::services::GetObserverService()) {
+    obs->AddObserver(this, "domwindowclosed", false);
+    obs->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+    mObserving = true;
+  }
+}
+
+void ZenMouseTracker::RemoveObservers() {
+  if (!mObserving) {
+    return;
+  }
+  if (nsCOMPtr<nsIObserverService> obs =
+          mozilla::services::GetObserverService()) {
+    obs->RemoveObserver(this, "domwindowclosed");
+    obs->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
+  }
+  mObserving = false;
+}
+
+NS_IMETHODIMP
+ZenMouseTracker::UnregisterWindow(mozIDOMWindowProxy* aWindow) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!aWindow) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  StopTrackingWindow(nsPIDOMWindowOuter::From(aWindow));
+  return NS_OK;
+}
+
+void ZenMouseTracker::StopTrackingWindow(nsPIDOMWindowOuter* aWindow) {
+  for (size_t i = 0; i < mTracked.Length(); i++) {
+    if (mTracked[i].mWindow == aWindow) {
+      mTracked.RemoveElementAt(i);
+      break;
+    }
+  }
+  OnTrackedListChanged();
+}
+
+void ZenMouseTracker::OnTrackedListChanged() {
+  if (mTracked.IsEmpty()) {
+    ZenNativeMouseMonitor::Stop();
+    RemoveObservers();
+  }
+}
+
+// static
+void ZenMouseTracker::OnNativePointerMove(const mozilla::DesktopPoint& aPoint) {
+  sLatestPointerX = int32_t(aPoint.x);
+  sLatestPointerY = int32_t(aPoint.y);
+  if (sPendingEvaluation.exchange(true)) {
+    // An already queued evaluation will pick up the position we just stored
+    return;
+  }
+  nsresult rv = NS_DispatchToMainThread(
+      NS_NewRunnableFunction("zen::ZenMouseTracker::Evaluate", [] {
+        sPendingEvaluation = false;
+        if (RefPtr<ZenMouseTracker> tracker = sInstance) {
+          tracker->Evaluate(mozilla::DesktopPoint(float(sLatestPointerX),
+                                                  float(sLatestPointerY)));
+        }
+      }));
+  if (NS_FAILED(rv)) {
+    // Don't let a failed dispatch (e.g. during shutdown) block all future
+    // evaluations
+    sPendingEvaluation = false;
+  }
+}
+
+void ZenMouseTracker::Evaluate(const mozilla::DesktopPoint& aPoint) {
+  nsTArray<nsCOMPtr<nsPIDOMWindowOuter>> exited;
+  for (size_t i = mTracked.Length(); i > 0; i--) {
+    auto& tracked = mTracked[i - 1];
+    RefPtr<nsIWidget> widget =
+        mozilla::widget::WidgetUtils::DOMWindowToWidget(tracked.mWindow);
+    if (!widget) {
+      mTracked.RemoveElementAt(i - 1);
+      continue;
+    }
+    if (!IsPointerWithinBounds(tracked, aPoint, widget)) {
+      exited.AppendElement(std::move(tracked.mWindow));
+      mTracked.RemoveElementAt(i - 1);
+    }
+  }
+  OnTrackedListChanged();
+
+  if (exited.IsEmpty()) {
+    return;
+  }
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (!obs) {
+    return;
+  }
+  for (auto& window : exited) {
+    obs->NotifyObservers(window, ZEN_MOUSE_TRACKER_EXITED_TOPIC, nullptr);
+  }
+}
+
+// static
+bool ZenMouseTracker::IsPointerWithinBounds(const TrackedWindow& aTracked,
+                                            const mozilla::DesktopPoint& aPoint,
+                                            nsIWidget* aWidget) {
+  const auto scale = aWidget->GetDesktopToDeviceScale();
+  const float x = aPoint.x * scale.scale;
+  const float y = aPoint.y * scale.scale;
+
+  const auto origin = aWidget->WidgetToScreenOffset();
+  const auto size = aWidget->GetClientSize();
+  const float left = origin.x;
+  const float top = origin.y;
+  const float right = left + size.width;
+  const float bottom = top + size.height;
+
+  if (x >= left && x <= right && y >= top && y <= bottom) {
+    // Back inside the window; the in-window hover logic owns this case
+    return true;
+  }
+
+  const float maxOffset =
+      aTracked.mMaxEdgeOffset * float(aWidget->GetDefaultScale().scale);
+  switch (aTracked.mEdge) {
+    case TrackedEdge::Left:
+      return x >= left - maxOffset && x < left && y >= top && y <= bottom;
+    case TrackedEdge::Right:
+      return x > right && x <= right + maxOffset && y >= top && y <= bottom;
+    case TrackedEdge::Top:
+      return y >= top - maxOffset && y < top && x >= left && x <= right;
+    case TrackedEdge::Bottom:
+      return y > bottom && y <= bottom + maxOffset && x >= left && x <= right;
+  }
+  return false;
+}
+
+NS_IMETHODIMP
+ZenMouseTracker::Observe(nsISupports* aSubject, const char* aTopic,
+                         const char16_t* aData) {
+  if (!strcmp(aTopic, "domwindowclosed")) {
+    if (nsCOMPtr<nsPIDOMWindowOuter> window = do_QueryInterface(aSubject)) {
+      StopTrackingWindow(window);
+    }
+    return NS_OK;
+  }
+  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    mTracked.Clear();
+    OnTrackedListChanged();
+  }
+  return NS_OK;
+}
+
+}  // namespace zen

src/zen/compact-mode/ZenMouseTracker.h

@@ -0,0 +1,92 @@
+/* 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/. */
+
+#ifndef mozilla_ZenMouseTracker_h_
+#define mozilla_ZenMouseTracker_h_
+
+#include "nsIZenMouseTracker.h"
+
+#include "mozilla/Maybe.h"
+#include "nsIObserver.h"
+#include "nsCOMPtr.h"
+#include "nsPIDOMWindow.h"
+#include "nsTArray.h"
+#include "Units.h"
+
+class nsIWidget;
+
+// Fired with the tracked window as subject once the pointer breaks the
+// tracking conditions; tracking for that window has already stopped.
+#define ZEN_MOUSE_TRACKER_EXITED_TOPIC "zen-mouse-tracker:exited"
+
+namespace zen {
+
+/**
+ * @brief Watches the global OS pointer position for registered windows and
+ *   notifies observers once the pointer moves too far away from the window
+ *   edge it left through.
+ */
+class ZenMouseTracker final : public nsIZenMouseTracker, public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIZENMOUSETRACKER
+  NS_DECL_NSIOBSERVER
+
+  ZenMouseTracker();
+
+  /**
+   * @brief Called by the platform backends whenever the OS pointer moves.
+   * @param aPoint The pointer position in desktop pixels, relative to the
+   *   origin of the (primary) screen. May be called outside of a clean event
+   *   loop iteration (e.g. from a low level hook), evaluation is coalesced
+   *   onto the main thread.
+   */
+  static void OnNativePointerMove(const mozilla::DesktopPoint& aPoint);
+
+ private:
+  ~ZenMouseTracker();
+
+  enum class TrackedEdge : uint8_t { Left, Right, Top, Bottom };
+
+  struct TrackedWindow {
+    nsCOMPtr<nsPIDOMWindowOuter> mWindow;
+    TrackedEdge mEdge;
+    float mMaxEdgeOffset;  // In CSS pixels
+  };
+
+  static mozilla::Maybe<TrackedEdge> ParseEdge(const nsACString& aScreenEdge);
+
+  /**
+   * @brief Check every tracked window against the given pointer position and
+   *   notify + stop tracking the ones the pointer moved too far away from.
+   */
+  void Evaluate(const mozilla::DesktopPoint& aPoint);
+
+  /**
+   * @brief Whether the pointer is still allowed to keep the window's edge
+   *   element open, given the window's bounds on screen.
+   */
+  static bool IsPointerWithinBounds(const TrackedWindow& aTracked,
+                                    const mozilla::DesktopPoint& aPoint,
+                                    nsIWidget* aWidget);
+
+  void StopTrackingWindow(nsPIDOMWindowOuter* aWindow);
+
+  /**
+   * @brief Tear down the native monitor and our observers once the last
+   *   tracked window is gone, so the service is fully idle while nothing is
+   *   being tracked.
+   */
+  void OnTrackedListChanged();
+
+  void AddObservers();
+  void RemoveObservers();
+
+  nsTArray<TrackedWindow> mTracked;
+  bool mObserving = false;
+};
+
+}  // namespace zen
+
+#endif

src/zen/compact-mode/ZenMouseTrackerCocoa.mm

@@ -0,0 +1,65 @@
+/* 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/. */
+
+#include "ZenMouseTracker.h"
+#include "ZenMouseTrackerInternal.h"
+
+#include "nsCocoaUtils.h"
+
+#import <Foundation/Foundation.h>
+#import <AppKit/AppKit.h>
+
+namespace zen {
+
+// The global monitor only sees events delivered to other applications, so a
+// local monitor is needed as well for moves that AppKit routes to our own
+// app while the pointer is outside of the tracked window (AppKit sends mouse
+// moved events to the key window regardless of the pointer position).
+static id sLocalMonitor = nil;
+static id sGlobalMonitor = nil;
+
+static void ReportPointerPosition() {
+  NSPoint point = [NSEvent mouseLocation];
+  point.y = nsCocoaUtils::FlippedScreenY(point.y);
+  ZenMouseTracker::OnNativePointerMove(
+      mozilla::DesktopPoint(float(point.x), float(point.y)));
+}
+
+nsresult ZenNativeMouseMonitor::Start() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  if (sLocalMonitor || sGlobalMonitor) {
+    return NS_OK;
+  }
+  const NSEventMask mask = NSEventMaskMouseMoved | NSEventMaskLeftMouseDragged |
+                           NSEventMaskRightMouseDragged |
+                           NSEventMaskOtherMouseDragged;
+  sLocalMonitor =
+      [NSEvent addLocalMonitorForEventsMatchingMask:mask
+                                            handler:^(NSEvent* aEvent) {
+                                              ReportPointerPosition();
+                                              return aEvent;
+                                            }];
+  sGlobalMonitor =
+      [NSEvent addGlobalMonitorForEventsMatchingMask:mask
+                                             handler:^(NSEvent* aEvent) {
+                                               ReportPointerPosition();
+                                             }];
+  return NS_OK;
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_NOT_AVAILABLE);
+}
+
+void ZenNativeMouseMonitor::Stop() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  if (sLocalMonitor) {
+    [NSEvent removeMonitor:sLocalMonitor];
+    sLocalMonitor = nil;
+  }
+  if (sGlobalMonitor) {
+    [NSEvent removeMonitor:sGlobalMonitor];
+    sGlobalMonitor = nil;
+  }
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+}  // namespace zen

src/zen/compact-mode/ZenMouseTrackerInternal.h

@@ -0,0 +1,48 @@
+/* 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/. */
+
+#ifndef mozilla_ZenMouseTrackerInternal_h_
+#define mozilla_ZenMouseTrackerInternal_h_
+
+#include "nscore.h"
+
+// On Linux there's no reliable way to observe the global pointer (Wayland
+// doesn't expose it at all), so we don't track there and callers fall back
+// to their timeout based behavior
+#if defined(XP_MACOSX) || defined(XP_WIN)
+#  define NS_ZEN_CAN_TRACK_POINTER 1
+#endif
+
+namespace zen {
+
+/**
+ * @brief Platform backend that delivers global pointer movements to
+ *   ZenMouseTracker::OnNativePointerMove, including movements outside of any
+ *   of our windows.
+ */
+class ZenNativeMouseMonitor final {
+ public:
+#ifdef NS_ZEN_CAN_TRACK_POINTER
+  /**
+   * @brief Start delivering pointer moves. Safe to call while already
+   *   started.
+   * @throws NS_ERROR_NOT_AVAILABLE when the platform cannot observe the
+   *   global pointer (e.g. on Linux).
+   */
+  static nsresult Start();
+  /**
+   * @brief Stop delivering pointer moves. Safe to call while stopped.
+   */
+  static void Stop();
+#else
+  static nsresult Start() { return NS_ERROR_NOT_AVAILABLE; }
+  static void Stop() {}
+#endif
+
+  ZenNativeMouseMonitor() = delete;
+};
+
+}  // namespace zen
+
+#endif

src/zen/compact-mode/ZenMouseTrackerWin.cpp

@@ -0,0 +1,51 @@
+/* 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/. */
+
+#include "ZenMouseTracker.h"
+#include "ZenMouseTrackerInternal.h"
+
+#include <windows.h>
+
+namespace zen {
+
+static HHOOK sMouseHook = nullptr;
+
+// Runs on the thread that installed the hook (the main thread). Keep this as
+// light as possible: the system silently removes hooks that take too long.
+static LRESULT CALLBACK MouseHookProc(int aCode, WPARAM aWParam,
+                                      LPARAM aLParam) {
+  if (aCode == HC_ACTION && aWParam == WM_MOUSEMOVE) {
+    const auto* info = reinterpret_cast<MSLLHOOKSTRUCT*>(aLParam);
+    // Screen physical pixels, which are what desktop pixels map to on Windows
+    ZenMouseTracker::OnNativePointerMove(
+        mozilla::DesktopPoint(float(info->pt.x), float(info->pt.y)));
+  }
+  return ::CallNextHookEx(nullptr, aCode, aWParam, aLParam);
+}
+
+nsresult ZenNativeMouseMonitor::Start() {
+  if (sMouseHook) {
+    return NS_OK;
+  }
+  // Pass the module that actually contains the hook proc (xul.dll), not the
+  // executable's module
+  HMODULE module = nullptr;
+  if (!::GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
+                                GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
+                            reinterpret_cast<LPCWSTR>(&MouseHookProc),
+                            &module)) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  sMouseHook = ::SetWindowsHookExW(WH_MOUSE_LL, MouseHookProc, module, 0);
+  return sMouseHook ? NS_OK : NS_ERROR_NOT_AVAILABLE;
+}
+
+void ZenNativeMouseMonitor::Stop() {
+  if (sMouseHook) {
+    ::UnhookWindowsHookEx(sMouseHook);
+    sMouseHook = nullptr;
+  }
+}
+
+}  // namespace zen

src/zen/compact-mode/components.conf

@@ -0,0 +1,14 @@
+# 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/.
+
+Classes = [
+    {
+        'cid': '{03d900f7-639f-4c81-b029-2883dd893ccb}',
+        'interfaces': ['nsIZenMouseTracker'],
+        'contract_ids': ['@mozilla.org/zen/mouse-tracker;1'],
+        'type': 'zen::ZenMouseTracker',
+        'headers': ['mozilla/ZenMouseTracker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+]

src/zen/compact-mode/moz.build

@@ -0,0 +1,37 @@
+# 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/.
+
+XPIDL_SOURCES += [
+    "nsIZenMouseTracker.idl",
+]
+
+EXPORTS.mozilla += [
+    "ZenMouseTracker.h",
+    "ZenMouseTrackerInternal.h",
+]
+
+SOURCES += [
+    "ZenMouseTracker.cpp",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+LOCAL_INCLUDES += [
+    "/widget",
+]
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "cocoa":
+    SOURCES += ["ZenMouseTrackerCocoa.mm"]
+    LOCAL_INCLUDES += [
+        "/widget/cocoa",
+        "/xpcom/base",
+    ]
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "windows":
+    SOURCES += ["ZenMouseTrackerWin.cpp"]
+
+FINAL_LIBRARY = "xul"
+XPIDL_MODULE = "zen_compact_mode"

src/zen/compact-mode/nsIZenMouseTracker.idl

@@ -0,0 +1,41 @@
+/* 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/. */
+
+#include "nsISupports.idl"
+
+interface mozIDOMWindowProxy;
+
+/**
+ * @brief Tracks the OS pointer for windows the pointer has left.
+ *   Once the pointer either crosses the window bounds on the
+ *   axis perpendicular to the registered edge, or moves further than the
+ *   given offset past that edge, the "zen-mouse-tracker:exited" observer
+ *   notification is fired with the window as subject and tracking for that
+ *   window stops.
+ */
+[scriptable, uuid(023e85e6-44e1-46b3-9cfb-6f3c7fa075f8)]
+interface nsIZenMouseTracker : nsISupports {
+  /**
+   * @brief Start tracking the pointer for the given window.
+   *
+   * Re-registering a window updates its edge and offset. Tracking is
+   * automatically cleared when the window is closed.
+   *
+   * @param window The window the pointer just left.
+   * @param screenEdge The edge the pointer left through, one of "left",
+   *   "right", "top" or "bottom".
+   * @param maxEdgeOffset How far (in CSS pixels) the pointer may travel past
+   *   screenEdge before the exit notification is fired.
+   * @throws NS_ERROR_NOT_AVAILABLE when the platform cannot track the global
+   *   pointer position (e.g. on Linux).
+   */
+  void registerWindow(in mozIDOMWindowProxy window, in ACString screenEdge,
+                      in float maxEdgeOffset);
+
+  /**
+   * @brief Stop tracking the pointer for the given window. No-op if the
+   *   window isn't being tracked.
+   */
+  void unregisterWindow(in mozIDOMWindowProxy window);
+};

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

@@ -654,6 +654,10 @@
     }
 
     #shouldSwitchSpace(event) {
+      if (document.documentElement.hasAttribute("customizing")) {
+        return { isNearLeftEdge: false, isNearRightEdge: false };
+      }
+
       const padding = Services.prefs.getIntPref(
         "zen.workspaces.dnd-switch-padding"
       );
@@ -722,10 +726,11 @@
 
     #handle_sidebarDragOver(event) {
       const dt = event.dataTransfer;
+      const isTabDrag = dt.mozTypesAt(0)[0] === TAB_DROP_TYPE;
 
       const { isNearLeftEdge, isNearRightEdge } =
         this.#shouldSwitchSpace(event);
-      if (isNearLeftEdge || isNearRightEdge) {
+      if (isTabDrag && (isNearLeftEdge || isNearRightEdge)) {
         if (!this.#changeSpaceTimer && !this.#isOutOfWindow) {
           this.#changeSpaceTimer = setTimeout(() => {
             this.clearDragOverVisuals();
@@ -749,6 +754,10 @@
 
     handle_spaceIconDragOver(event) {
       const dt = event.dataTransfer;
+      if (dt.mozTypesAt(0)[0] !== TAB_DROP_TYPE) {
+        return;
+      }
+
       const draggedTab = dt.mozGetDataAt(TAB_DROP_TYPE, 0);
       if (draggedTab.hasAttribute("zen-essential")) {
         return;

src/zen/drag-and-drop/moz.build

@@ -15,6 +15,11 @@ SOURCES += [
     "nsZenDragAndDrop.cpp",
 ]
 
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "cocoa":
+    SOURCES += ["nsZenNativeWindowMove.mm"]
+elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+
 XPCOM_MANIFESTS += [
     "components.conf",
 ]

src/zen/drag-and-drop/nsIZenDragAndDrop.idl

@@ -4,6 +4,8 @@
 
 #include "nsISupports.idl"
 
+interface mozIDOMWindowProxy;
+
 /**
  * @brief Interface for Zen's drag and drop functionality.
  */
@@ -21,4 +23,14 @@ interface nsIZenDragAndDrop : nsISupports {
    * @brief Indicate that a drag operation has ended.
    */
   void onDragEnd();
+
+  /**
+   * @brief Start a native, OS-driven interactive move of the window,
+   * as if the user had grabbed its titlebar. Must be called while the
+   * primary mouse button is held down. The OS takes over the drag,
+   * providing native behaviors like macOS window tiling or Windows
+   * snap layouts, and ends it when the button is released.
+   * @param window The chrome window to move.
+   */
+  void beginNativeWindowMove(in mozIDOMWindowProxy window);
 };

src/zen/drag-and-drop/nsZenDragAndDrop.cpp

@@ -5,7 +5,57 @@
 #include "nsZenDragAndDrop.h"
 #include "nsBaseDragService.h"
 
+#include "mozilla/WidgetUtils.h"
+#include "nsIWidget.h"
+#include "nsPIDOMWindow.h"
+
+#if defined(XP_WIN)
+#  include <windows.h>
+#elif defined(MOZ_WIDGET_GTK)
+#  include <gdk/gdk.h>
+#  include "mozilla/WidgetUtilsGtk.h"
+#endif
+
 namespace zen {
+
+#if defined(XP_MACOSX)
+nsresult StartNativeWindowMoveCocoa(nsIWidget* aWidget);
+#endif
+
+/**
+ * @brief Start a native, OS-driven move of the window backing aWidget.
+ * @see nsIZenDragAndDrop::beginNativeWindowMove for more details.
+ */
+static nsresult StartNativeWindowMove(nsIWidget* aWidget) {
+#if defined(XP_MACOSX)
+  return StartNativeWindowMoveCocoa(aWidget);
+#elif defined(XP_WIN)
+  HWND hwnd = static_cast<HWND>(aWidget->GetNativeData(NS_NATIVE_WINDOW));
+  NS_ENSURE_TRUE(hwnd, NS_ERROR_FAILURE);
+  // Hand the drag over to the OS as if the titlebar was grabbed; this
+  // enters the native move loop.
+  ::ReleaseCapture();
+  ::PostMessageW(hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0);
+  return NS_OK;
+#elif defined(MOZ_WIDGET_GTK)
+  auto* gdkWindow =
+      static_cast<GdkWindow*>(aWidget->GetNativeData(NS_NATIVE_WINDOW));
+  NS_ENSURE_TRUE(gdkWindow, NS_ERROR_FAILURE);
+  GdkWindow* toplevel = gdk_window_get_toplevel(gdkWindow);
+  GdkDevice* pointer = mozilla::widget::GdkGetPointer();
+  NS_ENSURE_TRUE(pointer, NS_ERROR_FAILURE);
+  // A native move works on both X11 and Wayland, unlike moving the
+  // window programmatically.
+  gint rootX = 0;
+  gint rootY = 0;
+  gdk_device_get_position(pointer, nullptr, &rootX, &rootY);
+  gdk_window_begin_move_drag_for_device(toplevel, pointer, 1, rootX, rootY,
+                                        GDK_CURRENT_TIME);
+  return NS_OK;
+#else
+  return NS_ERROR_NOT_IMPLEMENTED;
+#endif
+}
 namespace {
 
 static constexpr auto kZenDefaultDragImageOpacity =
@@ -44,4 +94,15 @@ nsZenDragAndDrop::OnDragEnd() {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsZenDragAndDrop::BeginNativeWindowMove(mozIDOMWindowProxy* aWindow) {
+  NS_ENSURE_ARG_POINTER(aWindow);
+  nsCOMPtr<nsPIDOMWindowOuter> outer = nsPIDOMWindowOuter::From(aWindow);
+  NS_ENSURE_TRUE(outer, NS_ERROR_INVALID_ARG);
+  RefPtr<nsIWidget> widget =
+      mozilla::widget::WidgetUtils::DOMWindowToWidget(outer);
+  NS_ENSURE_TRUE(widget, NS_ERROR_FAILURE);
+  return StartNativeWindowMove(widget);
+}
+
 }  // namespace zen

src/zen/drag-and-drop/nsZenNativeWindowMove.mm

@@ -0,0 +1,44 @@
+/* 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/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsDebug.h"
+#include "nsIWidget.h"
+#include "nsObjCExceptions.h"
+
+namespace zen {
+
+// Cocoa side of StartNativeWindowMove()
+nsresult StartNativeWindowMoveCocoa(nsIWidget* aWidget) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSWindow* window =
+      static_cast<NSWindow*>(aWidget->GetNativeData(NS_NATIVE_WINDOW));
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+
+  // performWindowDragWithEvent: needs a left-button event to start the
+  // WindowServer drag session. The triggering mousedown happened in a
+  // content process, so synthesize an equivalent event at the current
+  // mouse location.
+  NSPoint location = [window convertPointFromScreen:[NSEvent mouseLocation]];
+  NSEvent* event =
+      [NSEvent mouseEventWithType:NSEventTypeLeftMouseDragged
+                         location:location
+                    modifierFlags:0
+                        timestamp:NSProcessInfo.processInfo.systemUptime
+                     windowNumber:window.windowNumber
+                          context:nil
+                      eventNumber:0
+                       clickCount:1
+                         pressure:1.0];
+  NS_ENSURE_TRUE(event, NS_ERROR_FAILURE);
+
+  [window performWindowDragWithEvent:event];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+}  // namespace zen

src/zen/kbs/ZenKeyboardShortcuts.mjs

@@ -85,9 +85,10 @@ const defaultKeyboardGroups = {
     "zen-search-focus-shortcut",
     "zen-search-focus-shortcut-alt",
     "zen-find-shortcut",
-    "zen-search-find-again-shortcut-2",
     "zen-search-find-again-shortcut",
+    "zen-search-find-again-shortcut-alt",
     "zen-search-find-again-shortcut-prev",
+    "zen-search-find-again-shortcut-prev-alt",
   ],
   pageOperations: [
     "zen-text-action-copy-url-markdown-shortcut",
@@ -305,6 +306,29 @@ export class nsKeyShortcutModifiers {
 }
 
 class KeyShortcut {
+  static SHIFTED_SYMBOLS = {
+    1: "!",
+    2: "@",
+    3: "#",
+    4: "$",
+    5: "%",
+    6: "^",
+    7: "&",
+    8: "*",
+    9: "(",
+    0: ")",
+    "`": "~",
+    "-": "_",
+    "=": "+",
+    "[": "{",
+    "]": "}",
+    "\\": "|",
+    ";": ":",
+    "'": '"',
+    ",": "<",
+    ".": ">",
+    "/": "?",
+  };
   #id = "";
   #key = "";
   #keycode = "";
@@ -430,13 +454,35 @@ class KeyShortcut {
 
   replaceWithChild(key) {
     key.id = this.#id;
+
+    // When shift is pressed and the char changes when shifted (like 1 -> !),
+    // the XUL matches the shifted character so we need to emit the shifted character
+    // and drop the shift modifier so XUL can match
+    // This problem is also windows specific
+    let keyName = this.#key;
+    let modifiers = this.#modifiers;
+
+    if (AppConstants.platform == "win") {
+      const shiftedKey = KeyShortcut.SHIFTED_SYMBOLS[keyName];
+      if (shiftedKey && modifiers.shift) {
+        keyName = shiftedKey;
+        modifiers = new nsKeyShortcutModifiers(
+          modifiers.control,
+          modifiers.alt,
+          false, // -> for shift key
+          modifiers.meta,
+          modifiers.accel
+        );
+      }
+    }
+
     if (this.#keycode) {
       key.setAttribute("keycode", this.#keycode);
       key.removeAttribute("key");
-    } else if (this.#key) {
+    } else if (keyName) {
       // note to "mr. macos": Better use setAttribute, because without it, there's a
       //  risk of malforming the XUL element.
-      key.setAttribute("key", this.#key);
+      key.setAttribute("key", keyName);
       key.removeAttribute("keycode");
     } else {
       key.removeAttribute("key");
@@ -451,7 +497,7 @@ class KeyShortcut {
     if (this.#l10nId) {
       // key.setAttribute('data-l10n-id', this.#l10nId);
     }
-    key.setAttribute("modifiers", this.#modifiers.toString());
+    key.setAttribute("modifiers", modifiers.toString());
     if (this.#action) {
       key.setAttribute("command", this.#action);
     }
@@ -848,7 +894,7 @@ class nsZenKeyboardShortcutsLoader {
 }
 
 class nsZenKeyboardShortcutsVersioner {
-  static LATEST_KBS_VERSION = 19;
+  static LATEST_KBS_VERSION = 20;
 
   constructor() {}
 
@@ -1256,6 +1302,24 @@ class nsZenKeyboardShortcutsVersioner {
       }
     }
 
+    if (version < 20) {
+      // Migrate from version 19 to 20.
+      // - Disable "key_addTabSplitView" and "key_separateTabSplitView"
+      // since we already had "cmd_zenNewEmptySplit" and "cmd_zenSplitViewUnsplit" before Firefox 153.
+      // - Disable firefox's "viewOpenTabsSidebarKb" as it depends on firefox's native sidebar feature
+      const shouldBeDisabledShortcuts = [
+        "key_addTabSplitView",
+        "key_separateTabSplitView",
+        "viewOpenTabsSidebarKb",
+      ];
+      for (let shortcut of data) {
+        if (shouldBeDisabledShortcuts.includes(shortcut.getID())) {
+          shortcut.shouldBeEmpty = true;
+          shortcut.setDisabled(true);
+        }
+      }
+    }
+
     return data;
   }
 }

src/zen/moz.build

@@ -9,6 +9,7 @@ EXTRA_PP_COMPONENTS += [
 DIRS += [
     "boosts",
     "common",
+    "compact-mode",
     "drag-and-drop",
     "glance",
     "live-folders",
@@ -21,4 +22,5 @@ DIRS += [
     "spaces",
     "space-routing",
     "sync",
+    "window-drag",
 ]

src/zen/sessionstore/ZenWindowSync.sys.mjs

@@ -769,8 +769,8 @@ class nsZenWindowSync {
     const otherBrowser = aTab.linkedBrowser;
 
     // We aren't closing the other tab so, we also need to swap its tablisteners.
-    let filter = otherTabBrowser._tabFilters.get(aTab);
-    let tabListener = otherTabBrowser._tabListeners.get(aTab);
+    let filter = otherTabBrowser._getTabProgressFilter(aTab);
+    let tabListener = otherTabBrowser._getTabProgressListener(aTab);
     try {
       otherBrowser.webProgress.removeProgressListener(filter);
       filter.removeProgressListener(tabListener);
@@ -792,7 +792,7 @@ class nsZenWindowSync {
         true,
         false
       );
-      otherTabBrowser._tabListeners.set(aTab, tabListener);
+      otherTabBrowser._setTabProgressListener(aTab, tabListener);
 
       const notifyAll = Ci.nsIWebProgress.NOTIFY_ALL;
       filter.addProgressListener(tabListener, notifyAll);

src/zen/spaces/ZenSpaceCreation.mjs

@@ -2,6 +2,12 @@
  * 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.defineLazyGetter(lazy, "l10n", () => {
+  return new Localization(["browser/zen-workspaces.ftl"], true);
+});
+
 class nsZenWorkspaceCreation extends MozXULElement {
   #wasInCollapsedMode = false;
 
@@ -192,7 +198,7 @@ class nsZenWorkspaceCreation extends MozXULElement {
 
       this.currentProfile = {
         id: 0,
-        name: ContextualIdentityService.formatContextLabel("user-context-none"),
+        name: lazy.l10n.formatValueSync("zen-workspace-default-profile"),
       };
     } else {
       this.inputProfile.parentNode.hidden = true;
@@ -297,10 +303,19 @@ class nsZenWorkspaceCreation extends MozXULElement {
   }
 
   onProfilePopupShowing(event) {
-    return window.createUserContextMenu(event, {
+    window.createUserContextMenu(event, {
       isContextMenu: true,
       showDefaultTab: true,
+      showManageContainers: false,
     });
+
+    const defaultItem = event.target.querySelector('[data-usercontextid="0"]');
+    if (defaultItem) {
+      defaultItem.removeAttribute("data-l10n-id");
+      defaultItem.label = lazy.l10n.formatValueSync(
+        "zen-workspace-default-profile"
+      );
+    }
   }
 
   onProfilePopupCommand(event) {

src/zen/spaces/ZenSpaceManager.mjs

@@ -22,6 +22,10 @@ ChromeUtils.defineLazyGetter(lazy, "toolbarBackgroundElement", () => {
   return document.getElementById("zen-toolbar-background");
 });
 
+ChromeUtils.defineLazyGetter(lazy, "l10n", () => {
+  return new Localization(["browser/zen-workspaces.ftl"], true);
+});
+
 /**
  * Zen Spaces manager. This class is mainly responsible for the UI
  * and user interactions but it also contains some logic to manage
@@ -1263,11 +1267,19 @@ class nsZenWorkspaces {
       workspace = this.getActiveWorkspaceFromCache();
     }
     let containerTabId = workspace.containerTabId;
-    return window.createUserContextMenu(event, {
+    window.createUserContextMenu(event, {
       isContextMenu: true,
       excludeUserContextId: containerTabId,
       showDefaultTab: true,
     });
+
+    const defaultItem = event.target.querySelector('[data-usercontextid="0"]');
+    if (defaultItem) {
+      defaultItem.removeAttribute("data-l10n-id");
+      defaultItem.label = lazy.l10n.formatValueSync(
+        "zen-workspace-default-profile"
+      );
+    }
   }
 
   saveWorkspace(workspaceData) {

src/zen/spaces/create-workspace-form.css

@@ -26,7 +26,7 @@ zen-workspace-creation {
     }
 
     & form {
-      --input-bgcolor: light-dark(rgba(0, 0, 0, 0.05), rgba(255, 255, 255, 0.05));
+      --input-text-background-color: light-dark(rgba(0, 0, 0, 0.05), rgba(255, 255, 255, 0.05));
 
       display: flex;
       flex-direction: column;
@@ -53,7 +53,7 @@ zen-workspace-creation {
         padding: 9px 6px;
         border-radius: 8px !important;
         margin: 0;
-        background-color: var(--input-bgcolor);
+        background-color: var(--input-text-background-color);
         gap: 8px;
         align-items: center;
         padding-left: 8px;
@@ -108,7 +108,7 @@ zen-workspace-creation {
 
         & .zen-workspace-creation-name {
           --input-border-color: transparent;
-          --input-bgcolor: transparent;
+          --input-text-background-color: transparent;
           padding: 0 !important;
           width: 100%;
           outline: none;
@@ -120,7 +120,7 @@ zen-workspace-creation {
         padding: 4px;
         border-radius: 8px !important;
         margin: 0;
-        background-color: var(--input-bgcolor);
+        background-color: var(--input-text-background-color);
         gap: 4px;
         align-items: center;
         flex-wrap: wrap;
@@ -149,7 +149,7 @@ zen-workspace-creation {
       & .zen-workspace-creation-edit-theme-button {
         border-radius: 8px !important;
         margin: 0;
-        background-color: var(--input-bgcolor);
+        background-color: var(--input-text-background-color);
         justify-content: center;
         align-items: center;
         appearance: none;

src/zen/tabs/ZenPinnedTabManager.mjs

@@ -1019,12 +1019,15 @@ class nsZenPinnedTabManager extends nsZenDOMOperatedFeature {
   }
 
   canEssentialBeAdded(tab) {
+    const isExistingEssentialTab = tab.hasAttribute("zen-essential");
     return (
       !(
         (tab.getAttribute("usercontextid") || 0) !=
           (gZenWorkspaces.getActiveWorkspaceFromCache().containerTabId || 0) &&
         gZenWorkspaces.containerSpecificEssentials
-      ) && gBrowser._numZenEssentials < this.maxEssentialTabs
+      ) &&
+      (isExistingEssentialTab ||
+        gBrowser._numZenEssentials < this.maxEssentialTabs)
     );
   }
 

src/zen/tests/mochitests/shell/browser.toml

@@ -118,7 +118,19 @@ run-if = [
 ]
 tags = "os_integration"
 
+["browser_setDefaultProtocolHandler.js"]
+run-if = [
+  "os == 'win'",
+]
+tags = "os_integration"
+
 ["browser_setDesktopBackgroundPreview.js"]
 disabled="Disabled by import_external_tests.py"
-support-files = ["large.png"]
+support-files = ["large.png", "canvas.html"]
+tags = "os_integration"
+
+["browser_windowsSetDefaultAppCmdHandler.js"]
+run-if = [
+  "os == 'win'",
+]
 tags = "os_integration"

src/zen/tests/mochitests/shell/browser_headless_screenshot_1.js

@@ -71,4 +71,10 @@ add_task(async function () {
     ],
     screenshotPath
   );
+
+  // Regression test for bug 2003265, likely to become flaky if it regresses.
+  await testFileCreationPositive(
+    ["-url", "about:blank", "-screenshot", screenshotPath],
+    screenshotPath
+  );
 });

src/zen/tests/mochitests/shell/browser_setDefaultPDFHandler.js

@@ -8,6 +8,9 @@ ChromeUtils.defineESModuleGetters(this, {
   sinon: "resource://testing-common/Sinon.sys.mjs",
 });
 
+const confusedFoxPath = ShellService.getBundledPdfFile("confused_fox.pdf").path;
+const SET_HANDLER_WIN11 = Ci.nsIWindowsShellService.OPEN_WITH_SET_HANDLER;
+
 const setDefaultBrowserUserChoiceStub = sinon.stub();
 const setDefaultExtensionHandlersUserChoiceStub = sinon
   .stub()
@@ -34,17 +37,15 @@ const _userChoiceImpossibleTelemetryResultStub = sinon
 const setDefaultStub = sinon.stub();
 // We'll dynamically update this as needed during the tests.
 const queryCurrentDefaultHandlerForStub = sinon.stub();
-const launchOpenWithDefaultPickerForFileTypeStub = sinon.stub();
+const launchSetDefaultAppPickerStub = sinon.stub();
 const launchModernSettingsDialogDefaultAppsStub = sinon.stub();
 const shellStub = sinon.stub(ShellService, "shellService").value({
   setDefaultBrowser: setDefaultStub,
   queryCurrentDefaultHandlerFor: queryCurrentDefaultHandlerForStub,
-  QueryInterface: () => ({
-    launchOpenWithDefaultPickerForFileType:
-      launchOpenWithDefaultPickerForFileTypeStub,
-    launchModernSettingsDialogDefaultApps:
-      launchModernSettingsDialogDefaultAppsStub,
-  }),
+  launchSetDefaultAppPicker: launchSetDefaultAppPickerStub,
+  launchModernSettingsDialogDefaultApps:
+    launchModernSettingsDialogDefaultAppsStub,
+  QueryInterface: ChromeUtils.generateQI([]),
 });
 
 registerCleanupFunction(() => {
@@ -228,7 +229,7 @@ add_task(async function test_setAsDefaultPDFHandler_knownBrowser() {
   const expectedArguments = [aumi, [".pdf", "FirefoxPDF"]];
   const resetStubs = () => {
     setDefaultExtensionHandlersUserChoiceStub.resetHistory();
-    launchOpenWithDefaultPickerForFileTypeStub.resetHistory();
+    launchSetDefaultAppPickerStub.resetHistory();
     launchModernSettingsDialogDefaultAppsStub.resetHistory();
   };
 
@@ -250,7 +251,7 @@ add_task(async function test_setAsDefaultPDFHandler_knownBrowser() {
       "Called default browser agent with expected arguments"
     );
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.notCalled,
+      launchSetDefaultAppPickerStub.notCalled,
       "Did not fall back to open-with picker"
     );
     Assert.ok(
@@ -271,7 +272,7 @@ add_task(async function test_setAsDefaultPDFHandler_knownBrowser() {
       "Called default browser agent with expected arguments"
     );
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.notCalled,
+      launchSetDefaultAppPickerStub.notCalled,
       "Did not fall back to open-with picker"
     );
     Assert.ok(
@@ -289,7 +290,7 @@ add_task(async function test_setAsDefaultPDFHandler_knownBrowser() {
       "Did not use userChoice"
     );
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.notCalled,
+      launchSetDefaultAppPickerStub.notCalled,
       "Did not fall back to open-with picker"
     );
     Assert.ok(
@@ -310,7 +311,7 @@ add_task(async function test_setAsDefaultPDFHandler_knownBrowser() {
       "Called default browser agent with expected arguments"
     );
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.notCalled,
+      launchSetDefaultAppPickerStub.notCalled,
       "Did not fall back to open-with picker"
     );
     Assert.ok(
@@ -365,8 +366,11 @@ add_task(async function test_setAsDefaultPDFHandler_fallback() {
 
     Assert.ok(userChoiceStub.called, "Attempted userChoice");
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.calledWith(".pdf"),
-      "Fell back to open-with picker for .pdf"
+      launchSetDefaultAppPickerStub.calledWith(
+        confusedFoxPath,
+        SET_HANDLER_WIN11
+      ),
+      "Fell back to open-with picker with bundled PDF path and Win11 flag"
     );
     Assert.ok(
       launchModernSettingsDialogDefaultAppsStub.notCalled,
@@ -392,7 +396,7 @@ add_task(async function test_setAsDefaultPDFHandler_fallback() {
     );
     userChoiceStub.resetHistory();
     isDefaultHandlerForStub.resetHistory();
-    launchOpenWithDefaultPickerForFileTypeStub.resetHistory();
+    launchSetDefaultAppPickerStub.resetHistory();
     launchModernSettingsDialogDefaultAppsStub.resetHistory();
 
     info(
@@ -413,22 +417,25 @@ add_task(async function test_setAsDefaultPDFHandler_fallback() {
     isDefaultHandlerForStub.returns(true);
     userChoiceStub.resetHistory();
     isDefaultHandlerForStub.resetHistory();
-    launchOpenWithDefaultPickerForFileTypeStub.resetHistory();
+    launchSetDefaultAppPickerStub.resetHistory();
     launchModernSettingsDialogDefaultAppsStub.resetHistory();
 
     info(
       "When userChoice fails and open-with picker fails, should fall back to settings dialog"
     );
     Services.fog.testResetFOG();
-    launchOpenWithDefaultPickerForFileTypeStub.throws(
+    launchSetDefaultAppPickerStub.throws(
       new Error("mock IOpenWithLauncher failure")
     );
     await ShellService.setAsDefaultPDFHandler(false);
 
     Assert.ok(userChoiceStub.called, "Attempted userChoice");
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.calledWith(".pdf"),
-      "Attempted open-with picker for .pdf"
+      launchSetDefaultAppPickerStub.calledWith(
+        confusedFoxPath,
+        SET_HANDLER_WIN11
+      ),
+      "Attempted open-with picker with bundled PDF path and Win11 flag"
     );
     Assert.ok(
       launchModernSettingsDialogDefaultAppsStub.called,
@@ -463,7 +470,7 @@ add_task(async function test_setAsDefaultPDFHandler_fallback() {
     );
     userChoiceStub.resetHistory();
     isDefaultHandlerForStub.resetHistory();
-    launchOpenWithDefaultPickerForFileTypeStub.resetHistory();
+    launchSetDefaultAppPickerStub.resetHistory();
     launchModernSettingsDialogDefaultAppsStub.resetHistory();
 
     info(
@@ -499,7 +506,7 @@ add_task(async function test_setAsDefaultPDFHandler_fallback() {
       "Event result_is_default is false when no method set the default"
     );
   } finally {
-    launchOpenWithDefaultPickerForFileTypeStub.reset();
+    launchSetDefaultAppPickerStub.reset();
     launchModernSettingsDialogDefaultAppsStub.reset();
     sandbox.restore();
     await SpecialPowers.popPrefEnv();
@@ -529,7 +536,7 @@ add_task(async function test_setAsDefaultPDFHandler_useOpenWithDisabled() {
     await ShellService.setAsDefaultPDFHandler(false);
 
     Assert.ok(
-      launchOpenWithDefaultPickerForFileTypeStub.notCalled,
+      launchSetDefaultAppPickerStub.notCalled,
       "Did not invoke open-with picker when pref is disabled"
     );
     Assert.ok(
@@ -550,7 +557,7 @@ add_task(async function test_setAsDefaultPDFHandler_useOpenWithDisabled() {
       "Event result_is_default reflects isDefaultHandlerFor"
     );
   } finally {
-    launchOpenWithDefaultPickerForFileTypeStub.reset();
+    launchSetDefaultAppPickerStub.reset();
     launchModernSettingsDialogDefaultAppsStub.reset();
     sandbox.restore();
     await SpecialPowers.popPrefEnv();

src/zen/tests/mochitests/shell/browser_setDefaultProtocolHandler.js

@@ -0,0 +1,321 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+ChromeUtils.defineESModuleGetters(this, {
+  DEFAULT_PROTOCOL_URLS:
+    "moz-src:///browser/components/shell/ShellService.sys.mjs",
+  SET_DEFAULT_REDIRECT_PREF:
+    "moz-src:///browser/components/shell/WindowsSetDefaultRedirect.sys.mjs",
+  WindowsSetDefaultRedirect:
+    "moz-src:///browser/components/shell/WindowsSetDefaultRedirect.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+// Everything here is Windows.
+Assert.equal(AppConstants.platform, "win", "Platform is Windows");
+
+// Protocol defaults carry OPEN_WITH_PROTOCOL_MESSAGING on top of the
+// set-handler flag, unlike the file-type flags in browser_setDefaultPDFHandler.
+const SET_PROTOCOL_WIN11 =
+  Ci.nsIWindowsShellService.OPEN_WITH_SET_HANDLER |
+  Ci.nsIWindowsShellService.OPEN_WITH_PROTOCOL_MESSAGING;
+const SET_PROTOCOL_WIN10 =
+  Ci.nsIWindowsShellService.OPEN_WITH_SET_HANDLER_WIN10 |
+  Ci.nsIWindowsShellService.OPEN_WITH_PROTOCOL_MESSAGING;
+
+const launchSetDefaultAppPickerStub = sinon.stub();
+const launchModernSettingsDialogDefaultAppsStub = sinon.stub();
+const shellStub = sinon.stub(ShellService, "shellService").value({
+  launchSetDefaultAppPicker: launchSetDefaultAppPickerStub,
+  launchModernSettingsDialogDefaultApps:
+    launchModernSettingsDialogDefaultAppsStub,
+  QueryInterface: ChromeUtils.generateQI([]),
+});
+
+registerCleanupFunction(() => {
+  shellStub.restore();
+  Services.prefs.clearUserPref(SET_DEFAULT_REDIRECT_PREF);
+});
+
+function resetState() {
+  launchSetDefaultAppPickerStub.reset();
+  launchModernSettingsDialogDefaultAppsStub.reset();
+  Services.prefs.clearUserPref(SET_DEFAULT_REDIRECT_PREF);
+}
+
+function readPrefObject() {
+  return JSON.parse(
+    Services.prefs.getStringPref(SET_DEFAULT_REDIRECT_PREF, "")
+  );
+}
+
+add_task(async function test_default_https_uses_url_and_win11_flag() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+
+  try {
+    await ShellService.setAsDefaultProtocolHandler("https");
+
+    Assert.ok(
+      launchSetDefaultAppPickerStub.calledOnce,
+      "Picker invoked once for the https default"
+    );
+    Assert.deepEqual(
+      launchSetDefaultAppPickerStub.firstCall.args,
+      [DEFAULT_PROTOCOL_URLS.https, SET_PROTOCOL_WIN11],
+      "Picker called with https URL and SET_HANDLER | PROTOCOL_MESSAGING"
+    );
+    Assert.ok(
+      launchModernSettingsDialogDefaultAppsStub.notCalled,
+      "Modern settings not invoked when launcher succeeds"
+    );
+    Assert.deepEqual(
+      readPrefObject(),
+      {
+        openWithArg: DEFAULT_PROTOCOL_URLS.https,
+        overrideUri: null,
+        type: WindowsSetDefaultRedirect.TYPE.PROTOCOL,
+      },
+      "Pref records the URL; overrideUri null so the round-trip is suppressed"
+    );
+  } finally {
+    sandbox.restore();
+  }
+});
+
+add_task(async function test_custom_url_overrides_protocol_default() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+
+  try {
+    const customUrl = "https://custom.example.com/handler-check";
+    await ShellService.setAsDefaultProtocolHandler("https", customUrl, true);
+
+    Assert.deepEqual(
+      launchSetDefaultAppPickerStub.firstCall.args,
+      [customUrl, SET_PROTOCOL_WIN11],
+      "Picker called with caller-provided URL, not the protocol default"
+    );
+    Assert.deepEqual(
+      readPrefObject(),
+      {
+        openWithArg: customUrl,
+        overrideUri: DEFAULT_PROTOCOL_URLS.https,
+        type: WindowsSetDefaultRedirect.TYPE.PROTOCOL,
+      },
+      "Pref stashes the custom URL + protocol-default overrideUri for the round-trip"
+    );
+  } finally {
+    sandbox.restore();
+  }
+});
+
+add_task(async function test_win10_uses_set_handler_win10_flag() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(false);
+
+  try {
+    await ShellService.setAsDefaultProtocolHandler("https");
+    Assert.deepEqual(
+      launchSetDefaultAppPickerStub.firstCall.args,
+      [DEFAULT_PROTOCOL_URLS.https, SET_PROTOCOL_WIN10],
+      "Picker called with SET_HANDLER_WIN10 | PROTOCOL_MESSAGING when not on Win11"
+    );
+  } finally {
+    sandbox.restore();
+  }
+});
+
+add_task(async function test_falls_back_to_settings_when_picker_throws() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+  launchSetDefaultAppPickerStub.throws(new Error("mock launcher failure"));
+
+  try {
+    await ShellService.setAsDefaultProtocolHandler("https", undefined, true);
+
+    Assert.ok(launchSetDefaultAppPickerStub.called, "Tried picker first");
+    Assert.ok(
+      launchModernSettingsDialogDefaultAppsStub.called,
+      "Fell through to modern settings when launcher threw"
+    );
+    Assert.ok(
+      !Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+      "Pending redirect cleared on launcher failure so a later round-trip can't pick up stale intent"
+    );
+  } finally {
+    sandbox.restore();
+  }
+});
+
+add_task(async function test_unknown_protocol_with_no_url_throws() {
+  resetState();
+
+  await Assert.rejects(
+    ShellService.setAsDefaultProtocolHandler("notaprotocol"),
+    /No URL provided and no DEFAULT_PROTOCOL_URLS fallback/,
+    "Throws when neither URL nor protocol fallback resolves to a URL"
+  );
+  Assert.ok(
+    launchSetDefaultAppPickerStub.notCalled,
+    "Picker not invoked when args don't resolve to a URL"
+  );
+  Assert.ok(
+    !Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+    "Pref not touched when validation fails before any side effects"
+  );
+});
+
+// Wait for the deferred set_default_protocol_handler_attempt event to be
+// recorded, then return the single event emitted by the most recent call.
+async function awaitAttemptEvent() {
+  await TestUtils.waitForCondition(() => {
+    const events =
+      Glean.browser.setDefaultProtocolHandlerAttempt.testGetValue();
+    return events && events.length;
+  }, "Recorded set_default_protocol_handler_attempt event");
+  const events = Glean.browser.setDefaultProtocolHandlerAttempt.testGetValue();
+  Assert.equal(events.length, 1, "Recorded exactly one attempt event");
+  return events[0];
+}
+
+add_task(async function test_telemetry_records_open_with_success() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+  const isDefaultHandlerForStub = sandbox
+    .stub(ShellService, "isDefaultHandlerFor")
+    .returns(true);
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.shell.setDefaultProtocolHandler.attemptWaitTimeMs", 0]],
+  });
+
+  try {
+    Services.fog.testResetFOG();
+    await ShellService.setAsDefaultProtocolHandler("https");
+
+    const event = await awaitAttemptEvent();
+    Assert.equal(event.extra.method, "open_with", "Event method is open_with");
+    Assert.equal(event.extra.success, "true", "Event success is true");
+    Assert.equal(event.extra.protocol, "https", "Event protocol is https");
+    Assert.equal(
+      event.extra.result_is_default,
+      "true",
+      "Event result_is_default reflects isDefaultHandlerFor"
+    );
+    Assert.ok(
+      isDefaultHandlerForStub.calledWith("https"),
+      "Sampled isDefaultHandlerFor with the protocol"
+    );
+  } finally {
+    sandbox.restore();
+    await SpecialPowers.popPrefEnv();
+  }
+});
+
+add_task(async function test_telemetry_records_settings_fallback() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+  sandbox.stub(ShellService, "isDefaultHandlerFor").returns(true);
+  launchSetDefaultAppPickerStub.throws(new Error("mock launcher failure"));
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.shell.setDefaultProtocolHandler.attemptWaitTimeMs", 0]],
+  });
+
+  try {
+    Services.fog.testResetFOG();
+    await ShellService.setAsDefaultProtocolHandler("mailto");
+
+    Assert.equal(
+      Glean.browser.setDefaultProtocolHandlerModernSettingsResult.Success.testGetValue(),
+      1,
+      "Recorded modern settings success"
+    );
+
+    const event = await awaitAttemptEvent();
+    Assert.equal(
+      event.extra.method,
+      "settings",
+      "Event method is settings (last attempted)"
+    );
+    Assert.equal(
+      event.extra.success,
+      "true",
+      "Event success reflects modern settings launch"
+    );
+    Assert.equal(event.extra.protocol, "mailto", "Event protocol is mailto");
+  } finally {
+    sandbox.restore();
+    await SpecialPowers.popPrefEnv();
+  }
+});
+
+add_task(async function test_telemetry_records_complete_failure() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+  sandbox.stub(ShellService, "isDefaultHandlerFor").returns(false);
+  launchSetDefaultAppPickerStub.throws(new Error("mock launcher failure"));
+  launchModernSettingsDialogDefaultAppsStub.throws(
+    new Error("mock modern settings failure")
+  );
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.shell.setDefaultProtocolHandler.attemptWaitTimeMs", 0]],
+  });
+
+  try {
+    Services.fog.testResetFOG();
+    await ShellService.setAsDefaultProtocolHandler("https");
+
+    Assert.equal(
+      Glean.browser.setDefaultProtocolHandlerModernSettingsResult.Failure.testGetValue(),
+      1,
+      "Recorded modern settings failure"
+    );
+
+    const event = await awaitAttemptEvent();
+    Assert.equal(event.extra.method, "settings", "Event method is settings");
+    Assert.equal(
+      event.extra.success,
+      "false",
+      "Event success is false when every method failed"
+    );
+    Assert.equal(
+      event.extra.result_is_default,
+      "false",
+      "Event result_is_default is false when no method set the default"
+    );
+  } finally {
+    sandbox.restore();
+    await SpecialPowers.popPrefEnv();
+  }
+});
+
+add_task(async function test_overwrites_existing_pending_redirect() {
+  resetState();
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(ShellService, "_isWindows11").returns(true);
+
+  try {
+    // A differently-typed leftover value on the pref must not trip the
+    // setStringPref in WindowsSetDefaultRedirect.arm (it clears first).
+    Services.prefs.setBoolPref(SET_DEFAULT_REDIRECT_PREF, true);
+    await ShellService.setAsDefaultProtocolHandler("https", undefined, false);
+    Assert.deepEqual(
+      readPrefObject(),
+      {
+        openWithArg: DEFAULT_PROTOCOL_URLS.https,
+        overrideUri: null,
+        type: WindowsSetDefaultRedirect.TYPE.PROTOCOL,
+      },
+      "Stale value replaced with the structured redirect on the next call"
+    );
+  } finally {
+    sandbox.restore();
+  }
+});

src/zen/tests/mochitests/shell/browser_setDesktopBackgroundPreview.js

@@ -3,7 +3,7 @@
 
 /**
  * Check whether the preview image for setDesktopBackground is rendered
- * correctly, without stretching
+ * correctly, without stretching, for both <img> and <canvas> targets.
  */
 
 add_setup(async function () {
@@ -12,82 +12,85 @@ add_setup(async function () {
   });
 });
 
-add_task(async function () {
-  await BrowserTestUtils.withNewTab(
-    {
-      gBrowser,
-      url: getRootDirectory(gTestPath) + "large.png",
-    },
-    async () => {
-      const dialogLoad = BrowserTestUtils.domWindowOpened(null, async win => {
-        await BrowserTestUtils.waitForEvent(win, "load");
-        Assert.equal(
-          win.document.documentElement.getAttribute("windowtype"),
-          "Shell:SetDesktopBackground",
-          "Opened correct window"
-        );
-        return true;
-      });
+async function testPreview(url, targetSelector) {
+  await BrowserTestUtils.withNewTab({ gBrowser, url }, async browser => {
+    const dialogLoad = BrowserTestUtils.domWindowOpened(null, async win => {
+      await BrowserTestUtils.waitForEvent(win, "load");
+      Assert.equal(
+        win.document.documentElement.getAttribute("windowtype"),
+        "Shell:SetDesktopBackground",
+        "Opened correct window"
+      );
+      return true;
+    });
 
-      const image = content.document.images[0];
-      EventUtils.synthesizeMouseAtCenter(image, { type: "contextmenu" });
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      targetSelector,
+      { type: "contextmenu" },
+      browser
+    );
 
-      const menu = document.getElementById("contentAreaContextMenu");
-      await BrowserTestUtils.waitForPopupEvent(menu, "shown");
-      const menuClosed = BrowserTestUtils.waitForPopupEvent(menu, "hidden");
+    const menu = document.getElementById("contentAreaContextMenu");
+    await BrowserTestUtils.waitForPopupEvent(menu, "shown");
+    const menuClosed = BrowserTestUtils.waitForPopupEvent(menu, "hidden");
 
-      const menuItem = document.getElementById("context-setDesktopBackground");
-      try {
-        menu.activateItem(menuItem);
-      } catch (ex) {
-        ok(
-          menuItem.hidden,
-          "should only fail to activate when menu item is hidden"
-        );
-        ok(
-          !ShellService.canSetDesktopBackground,
-          "Should only hide when not able to set the desktop background"
-        );
-        is(
-          AppConstants.platform,
-          "linux",
-          "Should always be able to set desktop background on non-linux platforms"
-        );
-        todo(false, "Skipping test on this configuration");
-
-        menu.hidePopup();
-        await menuClosed;
-        return;
-      }
+    const menuItem = document.getElementById("context-setDesktopBackground");
+    try {
+      menu.activateItem(menuItem);
+    } catch (ex) {
+      ok(
+        menuItem.hidden,
+        "should only fail to activate when menu item is hidden"
+      );
+      ok(
+        !ShellService.canSetDesktopBackground,
+        "Should only hide when not able to set the desktop background"
+      );
+      is(
+        AppConstants.platform,
+        "linux",
+        "Should always be able to set desktop background on non-linux platforms"
+      );
+      todo(false, "Skipping test on this configuration");
 
+      menu.hidePopup();
       await menuClosed;
+      return;
+    }
 
-      const win = await dialogLoad;
+    await menuClosed;
 
-      /* setDesktopBackground.js does a setTimeout to wait for correct
+    const win = await dialogLoad;
+
+    /* setDesktopBackground.js does a setTimeout to wait for correct
        dimensions. If we don't wait here we could read the preview dimensions
        before they're changed to match the screen */
-      await TestUtils.waitForTick();
+    await TestUtils.waitForTick();
 
-      const canvas = win.document.getElementById("screen");
-      const screenRatio = screen.width / screen.height;
-      const previewRatio = canvas.clientWidth / canvas.clientHeight;
+    const canvas = win.document.getElementById("screen");
+    const screenRatio = screen.width / screen.height;
+    const previewRatio = canvas.clientWidth / canvas.clientHeight;
 
-      info(`Screen dimensions are ${screen.width}x${screen.height}`);
-      info(`Screen's raw ratio is ${screenRatio}`);
-      info(
-        `Preview dimensions are ${canvas.clientWidth}x${canvas.clientHeight}`
-      );
-      info(`Preview's raw ratio is ${previewRatio}`);
+    info(`Screen dimensions are ${screen.width}x${screen.height}`);
+    info(`Screen's raw ratio is ${screenRatio}`);
+    info(`Preview dimensions are ${canvas.clientWidth}x${canvas.clientHeight}`);
+    info(`Preview's raw ratio is ${previewRatio}`);
 
-      Assert.ok(
-        previewRatio < screenRatio + 0.01 && previewRatio > screenRatio - 0.01,
-        "Preview's aspect ratio is within ±.01 of screen's"
-      );
+    Assert.ok(
+      previewRatio < screenRatio + 0.01 && previewRatio > screenRatio - 0.01,
+      "Preview's aspect ratio is within ±.01 of screen's"
+    );
 
-      win.close();
+    win.close();
 
-      await menuClosed;
-    }
-  );
+    await menuClosed;
+  });
+}
+
+add_task(async function test_image() {
+  await testPreview(getRootDirectory(gTestPath) + "large.png", "img");
+});
+
+add_task(async function test_canvas() {
+  await testPreview(getRootDirectory(gTestPath) + "canvas.html", "canvas");
 });

src/zen/tests/mochitests/shell/browser_windowsSetDefaultAppCmdHandler.js

@@ -0,0 +1,293 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { CommandLineHandler } = ChromeUtils.importESModule(
+  "moz-src:///browser/components/shell/WindowsSetDefaultAppCmdHandler.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  BrowserWindowTracker: "resource:///modules/BrowserWindowTracker.sys.mjs",
+  SET_DEFAULT_REDIRECT_PREF:
+    "moz-src:///browser/components/shell/WindowsSetDefaultRedirect.sys.mjs",
+  ShellService: "moz-src:///browser/components/shell/ShellService.sys.mjs",
+  WindowsSetDefaultRedirect:
+    "moz-src:///browser/components/shell/WindowsSetDefaultRedirect.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+Assert.equal(AppConstants.platform, "win", "Platform is Windows");
+
+const confusedFoxPath = ShellService.getBundledPdfFile("confused_fox.pdf").path;
+const blankURISpec = Services.io.newFileURI(
+  ShellService.getBundledPdfFile("blank.pdf")
+).spec;
+
+const workingDir = Services.dirsvc.get("GreD", Ci.nsIFile);
+
+// Build a real nsICommandLine from an args array, so we exercise the same
+// flag-parsing the OS-initiated launch goes through
+function makeCmdLine(args, state = Ci.nsICommandLine.STATE_INITIAL_LAUNCH) {
+  return Cu.createCommandLine(args, workingDir, state);
+}
+
+// Arm the one-shot redirect via the real ShellService helper, the way
+// setAsDefault{*}Handler does right before launching the OS picker. These
+// tests all use file openWithArgs, so default the type.
+function armRedirect(
+  openWithArg,
+  overrideUri,
+  type = WindowsSetDefaultRedirect.TYPE.FILE
+) {
+  WindowsSetDefaultRedirect.arm(openWithArg, overrideUri, type);
+}
+
+let fakeWin;
+let getTopWindowStub;
+let openWindowStub;
+
+add_setup(function () {
+  fakeWin = { openTrustedLinkIn: sinon.stub() };
+  // Stubbed rather than spied: getTopWindow must return our fake window (and
+  // null on demand), and openWindow must not actually open a window in the
+  // test harness. We only inspect the calls.
+  getTopWindowStub = sinon.stub(BrowserWindowTracker, "getTopWindow");
+  openWindowStub = sinon.stub(BrowserWindowTracker, "openWindow");
+});
+
+registerCleanupFunction(() => {
+  sinon.restore();
+  Services.prefs.clearUserPref(SET_DEFAULT_REDIRECT_PREF);
+});
+
+function resetState() {
+  fakeWin.openTrustedLinkIn.resetHistory();
+  getTopWindowStub.reset();
+  getTopWindowStub.returns(fakeWin);
+  openWindowStub.reset();
+  Services.prefs.clearUserPref(SET_DEFAULT_REDIRECT_PREF);
+}
+
+add_task(async function test_no_osint_returns_early() {
+  resetState();
+  armRedirect(confusedFoxPath, blankURISpec);
+  const cmdLine = makeCmdLine(["-url", confusedFoxPath]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    false,
+    "preventDefault left untouched without -osint"
+  );
+  Assert.greaterOrEqual(
+    cmdLine.findFlag("url", false),
+    0,
+    "-url remains for the next handler"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "No tab opened without -osint"
+  );
+  Assert.ok(openWindowStub.notCalled, "No window opened without -osint");
+});
+
+add_task(async function test_osint_without_url_returns_early() {
+  resetState();
+  armRedirect(confusedFoxPath, blankURISpec);
+  const cmdLine = makeCmdLine(["-osint"]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    false,
+    "preventDefault left untouched without -url"
+  );
+  Assert.ok(fakeWin.openTrustedLinkIn.notCalled, "No tab opened without -url");
+  Assert.ok(openWindowStub.notCalled, "No window opened without -url");
+});
+
+add_task(async function test_no_pending_redirect_leaves_arg() {
+  // No armed redirect: even a -url that looks like our stub PDF is a real,
+  // user-initiated open (e.g. they double-clicked the file), so we must leave
+  // it for BrowserContentHandler.
+  resetState();
+
+  const cmdLine = makeCmdLine(["-osint", "-url", confusedFoxPath]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    false,
+    "preventDefault not set when no redirect is pending"
+  );
+  Assert.greaterOrEqual(
+    cmdLine.findFlag("url", false),
+    0,
+    "-url preserved for BrowserContentHandler"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "No tab opened when no redirect is pending"
+  );
+  Assert.ok(
+    openWindowStub.notCalled,
+    "No window opened when no redirect is pending"
+  );
+});
+
+add_task(async function test_unrelated_url_arg_is_ignored() {
+  resetState();
+  armRedirect(confusedFoxPath, blankURISpec);
+
+  const cmdLine = makeCmdLine([
+    "-osint",
+    "-url",
+    "https://example.com/some-page",
+  ]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    false,
+    "preventDefault not set for a -url that isn't the pending openWithArg"
+  );
+  Assert.greaterOrEqual(
+    cmdLine.findFlag("url", false),
+    0,
+    "-url preserved for subsequent handler"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "No tab opened for an unrelated -url"
+  );
+  Assert.ok(
+    Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+    "Pending redirect untouched when the openWithArg doesn't match"
+  );
+});
+
+add_task(async function test_suppress_only_when_target_null() {
+  resetState();
+  armRedirect(confusedFoxPath, null);
+
+  const cmdLine = makeCmdLine(["-osint", "-url", confusedFoxPath]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    true,
+    "openWithArg suppressed so BrowserContentHandler skips it"
+  );
+  Assert.equal(
+    cmdLine.findFlag("url", false),
+    -1,
+    "-url consumed even with no redirect target"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "No redirect when target is null"
+  );
+  Assert.ok(openWindowStub.notCalled, "No fallback window when target is null");
+  Assert.ok(
+    !Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+    "Redirect intent consumed"
+  );
+});
+
+add_task(async function test_redirects_to_top_window() {
+  resetState();
+  armRedirect(confusedFoxPath, blankURISpec);
+
+  const cmdLine = makeCmdLine(["-osint", "-url", confusedFoxPath]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    true,
+    "Default open suppressed for the pending openWithArg"
+  );
+  Assert.equal(cmdLine.findFlag("url", false), -1, "-url consumed");
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.calledOnce,
+    "Redirected into the top window"
+  );
+  Assert.deepEqual(fakeWin.openTrustedLinkIn.firstCall.args, [
+    blankURISpec,
+    "tab",
+  ]);
+  Assert.ok(openWindowStub.notCalled, "No new window when one exists");
+  Assert.ok(
+    !Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+    "Redirect intent is one-shot and cleared after use"
+  );
+});
+
+add_task(async function test_opens_new_window_when_no_top() {
+  resetState();
+  getTopWindowStub.returns(null);
+  armRedirect(confusedFoxPath, blankURISpec);
+
+  const cmdLine = makeCmdLine(["-osint", "-url", confusedFoxPath]);
+  new CommandLineHandler().handle(cmdLine);
+
+  Assert.equal(
+    cmdLine.preventDefault,
+    true,
+    "Default open suppressed even when no top window exists"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "Top-window path skipped when getTopWindow returns null"
+  );
+  Assert.ok(openWindowStub.calledOnce, "Falls back to openWindow");
+
+  const opts = openWindowStub.firstCall.args[0];
+  Assert.ok(
+    opts && opts.args,
+    "openWindow called with a {args} options object"
+  );
+  Assert.ok(
+    opts.args instanceof Ci.nsISupportsString,
+    "args is an nsISupportsString"
+  );
+  Assert.equal(
+    opts.args.data,
+    blankURISpec,
+    "nsISupportsString carries the redirect URI"
+  );
+  Assert.ok(
+    !Services.prefs.prefHasUserValue(SET_DEFAULT_REDIRECT_PREF),
+    "Redirect intent is one-shot and cleared after use"
+  );
+});
+
+add_task(async function test_intent_is_one_shot() {
+  resetState();
+  armRedirect(confusedFoxPath, blankURISpec);
+
+  new CommandLineHandler().handle(
+    makeCmdLine(["-osint", "-url", confusedFoxPath])
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.calledOnce,
+    "First call honors the pending redirect"
+  );
+
+  fakeWin.openTrustedLinkIn.resetHistory();
+  const second = makeCmdLine(["-osint", "-url", confusedFoxPath]);
+  new CommandLineHandler().handle(second);
+
+  Assert.equal(
+    second.preventDefault,
+    false,
+    "Second call leaves the openWithArg alone because the intent was consumed"
+  );
+  Assert.greaterOrEqual(
+    second.findFlag("url", false),
+    0,
+    "-url preserved on the second call (no pending redirect)"
+  );
+  Assert.ok(
+    fakeWin.openTrustedLinkIn.notCalled,
+    "Second call does not redirect"
+  );
+});

src/zen/tests/mochitests/shell/canvas.html

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<body>
+<canvas id="c" width="200" height="100"></canvas>
+<script>
+  const ctx = document.getElementById("c").getContext("2d");
+  ctx.fillStyle = "red";
+  ctx.fillRect(0, 0, 200, 100);
+</script>
+</body>
+</html>

src/zen/tests/mochitests/shell/unit/test_dynamicLauncher.js

@@ -0,0 +1,657 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  ShellService: "moz-src:///browser/components/shell/ShellService.sys.mjs",
+  Subprocess: "resource://gre/modules/Subprocess.sys.mjs",
+  TestUtils: "resource://testing-common/TestUtils.sys.mjs",
+  XPCOMUtils: "resource://gre/modules/XPCOMUtils.sys.mjs",
+});
+
+// This tests the browser's interaction with the Dynamic Launcher portal, which
+// is documented at
+//
+//   https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.DynamicLauncher
+
+XPCOMUtils.defineLazyServiceGetter(
+  this,
+  "IniParserFactory",
+  "@mozilla.org/xpcom/ini-parser-factory;1",
+  Ci.nsIINIParserFactory
+);
+
+function desktopEntryFromObject(object) {
+  let ini = IniParserFactory.createINIParser().QueryInterface(
+    Ci.nsIINIParserWriter
+  );
+
+  for (const property of Object.getOwnPropertyNames(object)) {
+    ini.setString("Desktop Entry", property, "" + object[property]);
+  }
+
+  return ini;
+}
+
+function objectFromDesktopEntry(aINI) {
+  let ini = IniParserFactory.createINIParser();
+  ini.initFromString(aINI);
+
+  let sections = ini.getSections();
+  ok(sections.hasMore(), "There is at least one section");
+  Assert.equal(sections.getNext(), "Desktop Entry", "First key is correct");
+  Assert.equal(sections.hasMore(), false, "...and there aren't others");
+
+  let keys = ini.getKeys("Desktop Entry");
+  let result = Object.create(null);
+  while (keys.hasMore()) {
+    let key = keys.getNext();
+    result[key] = ini.getString("Desktop Entry", key);
+  }
+
+  return result;
+}
+
+const portalBusName = "org.freedesktop.portal.Desktop";
+const portalObjectPath = "/org/freedesktop/portal/desktop";
+const portalInterfaceName = "org.freedesktop.portal.DynamicLauncher";
+const dbusMockInterface = "org.freedesktop.DBus.Mock";
+const addObjectMethod = `${dbusMockInterface}.AddObject`;
+const addMethodMethod = `${dbusMockInterface}.AddMethod`;
+const emitSignalDetailedMethod = `${dbusMockInterface}.EmitSignalDetailed`;
+const getCallsMethod = `${dbusMockInterface}.GetCalls`;
+const clearCallsMethod = `${dbusMockInterface}.ClearCalls`;
+const resetMethod = `${dbusMockInterface}.Reset`;
+const mockRequestObjectPath = "/org/freedesktop/portal/desktop/request";
+
+var DBUS_SESSION_BUS_ADDRESS = "";
+var DBUS_SESSION_BUS_PID = 0; // eslint-disable-line no-unused-vars
+var DBUS_MOCK = null;
+var gdbusCmd = null;
+
+async function callDbusMethod(objectPath, methodName, args) {
+  let mockProcess = await Subprocess.call({
+    command: gdbusCmd,
+    arguments: [
+      "call",
+      "--session",
+      "-d",
+      portalBusName,
+      "-o",
+      objectPath,
+      "-m",
+      methodName,
+      ...args,
+    ],
+  });
+  return mockProcess.wait();
+}
+
+// Launches a D-Bus daemon that the tests will run under, and sets it (via
+// environment variables) to be used as the D-Bus connection. Additionally, sets
+// up dbusmock to allow the test to create fake D-Bus objects; this avoids
+// needing to display UI to the user, or depending on the details of the
+// specific portal they have installed.
+add_setup(async function setup() {
+  // Start and use a separate message bus for the tests, to not interfere with
+  // the current's session message bus.
+  let dbus = await Subprocess.call({
+    command: await Subprocess.pathSearch("dbus-launch"),
+  });
+  await dbus.wait();
+  let stdout = await dbus.stdout.readString();
+  let lines = stdout.split("\n");
+  for (let i in lines) {
+    let tokens = lines[i].split("=");
+    switch (tokens.shift()) {
+      case "DBUS_SESSION_BUS_ADDRESS":
+        DBUS_SESSION_BUS_ADDRESS = tokens.join("=");
+        break;
+      case "DBUS_SESSION_BUS_PID":
+        DBUS_SESSION_BUS_PID = tokens.join();
+        break;
+      default:
+    }
+  }
+
+  gdbusCmd = await Subprocess.pathSearch("gdbus");
+
+  Services.env.set("DBUS_SESSION_BUS_ADDRESS", DBUS_SESSION_BUS_ADDRESS);
+  Services.env.set("GTK_USE_PORTAL", "1");
+
+  // dbusmock is used to mock the native messaging portal's D-Bus API.
+  DBUS_MOCK = await Subprocess.call({
+    command: await Subprocess.pathSearch("python3"),
+    arguments: [
+      "-m",
+      "dbusmock",
+      portalBusName,
+      portalObjectPath,
+      portalInterfaceName,
+      // vvvvvvvvvvvvv why is this needed?!
+      "-l",
+      "/dev/null",
+    ],
+  });
+
+  // Wait until dbusmock is ready
+  await TestUtils.waitForCondition(async () => {
+    let res = await callDbusMethod(
+      portalObjectPath,
+      "org.freedesktop.DBus.Mock.GetCalls",
+      []
+    );
+    return res.exitCode == 0;
+  }, "waiting for dbusmock");
+
+  registerCleanupFunction(async function () {
+    await DBUS_MOCK.kill();
+    // XXX: While this works locally, it consistently fails when tests are run
+    // in CI, with "xpcshell return code: -15". This needs to be investigated
+    // further. This leaves a stray dbus-daemon process behind,
+    // which isn't ideal, but is harmless.
+    /*await lazy.Subprocess.call({
+      command: await lazy.Subprocess.pathSearch("kill"),
+      arguments: ["-SIGQUIT", DBUS_SESSION_BUS_PID],
+    });*/
+  });
+});
+
+/**
+ * Determines who called the corresponding D-Bus method. dbusmock doesn't
+ * provide this information, but we need it to create a portal Request path, so
+ * this uses a one-off dbus-monitor instead.
+ *
+ * This function has two phases, determined by the promises in its return value:
+ *
+ *   - monitorReady will resolve when dbus-monitor appears to be awake. At this
+ *     point, the method call should happen.
+ *
+ *   - senderPromise will resolve when the call is detected. This will resolve
+ *     to the sender of the method call.
+ *
+ * @param {string} method
+ *   The method call to look for. (Currently you can't key based on the object
+ *   path.)
+ * @returns {{monitorReady:Promise<undefined>,senderPromise:Promise<string>}}
+ *   A set of promises corresponding to the current 'phase' of the check.
+ */
+function sniffDbusMethodCaller(method) {
+  let readyResolvers = Promise.withResolvers();
+  let doneResolvers = Promise.withResolvers();
+
+  // Use .then here so this can be a synchronous function, so you don't
+  // additionally have to worry about the promise returned.
+  Subprocess.pathSearch("dbus-monitor")
+    .then(command =>
+      Subprocess.call({
+        command,
+        arguments: ["--session"],
+      })
+    )
+    .then(async process => {
+      while (true) {
+        for (const line of (await process.stdout.readString()).split("\n")) {
+          readyResolvers.resolve();
+
+          // Extract the sender name from the dbus-monitor process's output.
+          if (
+            line.startsWith("method call") &&
+            line.includes(`member=${method}`)
+          ) {
+            let match = line.match(/sender=(\S*)/);
+            ok(match, "dbus-monitor output informs us of the sender");
+            doneResolvers.resolve(match[1]);
+            await process.kill();
+            return;
+          }
+        }
+      }
+    })
+    .finally(err => {
+      readyResolvers.reject(err);
+      doneResolvers.reject(err);
+    });
+
+  return {
+    monitorReady: readyResolvers.promise,
+    senderPromise: doneResolvers.promise,
+  };
+}
+
+/**
+ * Waits for a D-Bus method call with the given object path, method, and
+ * position in time (in case multiple calls happened).
+ *
+ * @param {string} objectPath
+ *   The object path the call should be for. This must be a dbusmock-based mock
+ *   object.
+ * @param {string} method
+ *   The method to get information for.
+ * @param {number} offset
+ *   Indicates that information should be returned for the nth (zero-based)
+ *   call.
+ * @returns {{offset:number,params:string}}
+ *   The offset after this call as a number (zero if it wasn't called), and the
+ *   string representation of the arguments; e.g. "'abc', 'def'".
+ */
+async function expectDbusMockCall(objectPath, method, offset) {
+  let getCalls = await Subprocess.call({
+    command: gdbusCmd,
+    arguments: [
+      "call",
+      "--session",
+      "-d",
+      portalBusName,
+      "-o",
+      objectPath,
+      "-m",
+      getCallsMethod,
+    ],
+  });
+  let out = "";
+  while (!out.endsWith("\n")) {
+    out += await getCalls.stdout.readString();
+  }
+  // The other regexes are fragile, so remove the byte arrays that break them.
+  out = out.replaceAll(/<\('bytes', <\[byte 0x[0-9a-fx, ]+\]>\)>/g, "<bytes>");
+  out = out.match(/\((@a\(tsav\) )?\[(.*)\],\)/)[2];
+  let calls = out.matchAll(/\(.*?\),?/g);
+  let methodCalled = false;
+  let params = {};
+  let i = 0;
+  for (let call of calls) {
+    if (i++ < offset) {
+      continue;
+    }
+    let matches = call[0].match(
+      /\((uint64 )?(?<timestamp>\d+), '(?<method>\w+)', (@av )?\[(?<params>.*)\]\),?/
+    );
+    ok(parseFloat(matches.groups.timestamp), "timestamp is valid");
+    if (matches.groups.method == method) {
+      methodCalled = true;
+      params = matches.groups.params;
+      break;
+    }
+  }
+  if (method) {
+    ok(methodCalled, `The ${method} mock was called`);
+  } else {
+    equal(i, 0, "No method mock was called");
+  }
+
+  await getCalls.wait();
+  return { offset: i, params };
+}
+
+add_task(async function test_successful_creation() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "PrepareInstall",
+    "ssva{sv}",
+    "o",
+    `ret = "/should/not/be/used"`,
+  ]);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path +
+      "/favicon-normal16.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  let { monitorReady, senderPromise } = sniffDbusMethodCaller("PrepareInstall");
+  await monitorReady;
+
+  let promise = ShellService.requestInstallDynamicLauncher("a.b.c", ini, null);
+
+  let senderName = await senderPromise;
+  let result = await expectDbusMockCall(portalObjectPath, "PrepareInstall", 0);
+  let [parentWindow, name, icon] = result.params.split(", ");
+  Assert.equal(parentWindow, "<''>", "No parent window was provided");
+  Assert.equal(name, "<'Example Launcher Name'>", "Launcher name was provided");
+  Assert.equal(icon, "<bytes>", "Icon was some sequence of bytes");
+
+  let match = result.params.match(/'handle_token': <'(?<token>.*)'>/);
+  ok(match, "Start arguments contain a handle token");
+  let handleToken = match.groups.token;
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "Install",
+    "sssa{sv}",
+    "",
+    "",
+  ]);
+
+  // Mock the Request object that is expected to be created in response to
+  // calling the Start method on the native messaging portal, wait for it to be
+  // available, and emit its Response signal.
+  let requestPath = `${mockRequestObjectPath}/${senderName
+    .slice(1)
+    .replace(".", "_")}/${handleToken}`;
+  await callDbusMethod(portalObjectPath, addObjectMethod, [
+    requestPath,
+    "org.freedesktop.portal.Request",
+    "@a{sv} {}",
+    "@a(ssss) []",
+  ]);
+  await callDbusMethod(requestPath, emitSignalDetailedMethod, [
+    "org.freedesktop.portal.Request",
+    "Response",
+    "ua{sv}",
+    `[<uint32 0>, <@a{sv} {'token': <'qwerty'>}>]`,
+    `{'destination': <'${senderName}'>}`,
+  ]);
+
+  // Verify that the Install method was called as expected after the Start
+  // request completed.
+  result = await expectDbusMockCall(portalObjectPath, "Install", result.offset);
+  let [token, desktopFileId, desktopEntry] = result.params.split(", ");
+  Assert.equal(token, "<'qwerty'>", "Correct token is provided");
+  Assert.equal(
+    desktopFileId,
+    "<'a.b.c.desktop'>",
+    "Correct desktop file ID is provided"
+  );
+
+  desktopEntry = desktopEntry
+    .replace(/^<'/, "")
+    .replace(/'>$/, "")
+    .replaceAll(/\\n/g, "\n");
+  let entry = objectFromDesktopEntry(desktopEntry);
+  Assert.deepEqual(entry, object, "Desktop entry contains expected values");
+
+  // Check for exceptions etc.
+  await promise;
+});
+
+add_task(async function test_prepareinstall_error() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "PrepareInstall",
+    "ssva{sv}",
+    "o",
+    `raise dbus.exceptions.DBusException("prepareinstall failed", name="org.mozilla.Error.Mocked")`,
+  ]);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path +
+      "/favicon-normal16.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  await Assert.rejects(
+    (async () =>
+      ShellService.requestInstallDynamicLauncher("a.b.c", ini, null))(),
+    /.*prepareinstall failed.*/,
+    "Failure was propagated from D-Bus"
+  );
+});
+
+add_task(async function test_install_error() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "PrepareInstall",
+    "ssva{sv}",
+    "o",
+    `ret = "/should/not/be/used"`,
+  ]);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path +
+      "/favicon-normal16.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  let { monitorReady, senderPromise } = sniffDbusMethodCaller("PrepareInstall");
+  await monitorReady;
+
+  let promise = ShellService.requestInstallDynamicLauncher("a.b.c", ini, null);
+
+  let senderName = await senderPromise;
+  let result = await expectDbusMockCall(portalObjectPath, "PrepareInstall", 0);
+
+  let match = result.params.match(/'handle_token': <'(?<token>.*)'>/);
+  ok(match, "Start arguments contain a handle token");
+  let handleToken = match.groups.token;
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "Install",
+    "sssa{sv}",
+    "",
+    `raise dbus.exceptions.DBusException("plain install failed", name="org.mozilla.Error.Mocked")`,
+  ]);
+
+  // Mock the Request object that is expected to be created in response to
+  // calling the Start method on the native messaging portal, wait for it to be
+  // available, and emit its Response signal.
+  let requestPath = `${mockRequestObjectPath}/${senderName
+    .slice(1)
+    .replace(".", "_")}/${handleToken}`;
+  await callDbusMethod(portalObjectPath, addObjectMethod, [
+    requestPath,
+    "org.freedesktop.portal.Request",
+    "@a{sv} {}",
+    "@a(ssss) []",
+  ]);
+  await callDbusMethod(requestPath, emitSignalDetailedMethod, [
+    "org.freedesktop.portal.Request",
+    "Response",
+    "ua{sv}",
+    `[<uint32 0>, <@a{sv} {'token': <'qwerty'>}>]`,
+    `{'destination': <'${senderName}'>}`,
+  ]);
+
+  result = await expectDbusMockCall(portalObjectPath, "Install", result.offset);
+  await Assert.rejects(
+    promise,
+    /.*plain install failed.*/,
+    "Promise rejected with expected content."
+  );
+});
+
+add_task(async function test_negativeResponseFromPrepareInstall() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "PrepareInstall",
+    "ssva{sv}",
+    "o",
+    `ret = "/should/not/be/used"`,
+  ]);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path +
+      "/favicon-normal16.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  let { monitorReady, senderPromise } = sniffDbusMethodCaller("PrepareInstall");
+  await monitorReady;
+
+  let promise = ShellService.requestInstallDynamicLauncher("a.b.c", ini, null);
+
+  let senderName = await senderPromise;
+  let result = await expectDbusMockCall(portalObjectPath, "PrepareInstall", 0);
+
+  let match = result.params.match(/'handle_token': <'(?<token>.*)'>/);
+  ok(match, "Start arguments contain a handle token");
+  let handleToken = match.groups.token;
+
+  let requestPath = `${mockRequestObjectPath}/${senderName
+    .slice(1)
+    .replace(".", "_")}/${handleToken}`;
+  await callDbusMethod(portalObjectPath, addObjectMethod, [
+    requestPath,
+    "org.freedesktop.portal.Request",
+    "@a{sv} {}",
+    "@a(ssss) []",
+  ]);
+  await callDbusMethod(requestPath, emitSignalDetailedMethod, [
+    "org.freedesktop.portal.Request",
+    "Response",
+    "ua{sv}",
+    `[<uint32 2>, <@a{sv} {}>]`,
+    `{'destination': <'${senderName}'>}`,
+  ]);
+
+  await Assert.rejects(
+    promise,
+    /.*Response was non-zero.*/,
+    "Promise rejected with expected content."
+  );
+});
+
+add_task(async function test_missingTokenFromPrepareInstall() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "PrepareInstall",
+    "ssva{sv}",
+    "o",
+    `ret = "/should/not/be/used"`,
+  ]);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path +
+      "/favicon-normal16.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  let { monitorReady, senderPromise } = sniffDbusMethodCaller("PrepareInstall");
+  await monitorReady;
+
+  let promise = ShellService.requestInstallDynamicLauncher("a.b.c", ini, null);
+
+  let senderName = await senderPromise;
+  let result = await expectDbusMockCall(portalObjectPath, "PrepareInstall", 0);
+
+  let match = result.params.match(/'handle_token': <'(?<token>.*)'>/);
+  ok(match, "Start arguments contain a handle token");
+  let handleToken = match.groups.token;
+
+  let requestPath = `${mockRequestObjectPath}/${senderName
+    .slice(1)
+    .replace(".", "_")}/${handleToken}`;
+  await callDbusMethod(portalObjectPath, addObjectMethod, [
+    requestPath,
+    "org.freedesktop.portal.Request",
+    "@a{sv} {}",
+    "@a(ssss) []",
+  ]);
+  await callDbusMethod(requestPath, emitSignalDetailedMethod, [
+    "org.freedesktop.portal.Request",
+    "Response",
+    "ua{sv}",
+    `[<uint32 0>, <@a{sv} {}>]`,
+    `{'destination': <'${senderName}'>}`,
+  ]);
+
+  await Assert.rejects(
+    promise,
+    /.*No token was provided from the portal.*/,
+    "Promise rejected with expected content."
+  );
+});
+
+add_task(async function test_bad_icon() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  let object = {
+    Version: "1.5",
+    Type: "Application",
+    Name: "Example Launcher Name",
+    Icon:
+      Services.dirsvc.get("CurWorkD", Ci.nsIFile).path + "/does-not-exist.png",
+    Exec: "browser command",
+  };
+  let ini = desktopEntryFromObject(object);
+
+  await Assert.rejects(
+    (async () =>
+      ShellService.requestInstallDynamicLauncher("a.b.c", ini, null))(),
+    /.*Failed to open .*png.*/,
+    "The resulting error should indicate that the file wasn't found."
+  );
+});
+
+add_task(async function test_uninstall_success() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "Uninstall",
+    "sa{sv}",
+    "",
+    ``,
+  ]);
+
+  await ShellService.requestUninstallDynamicLauncher("a.b.c");
+  let result = await expectDbusMockCall(portalObjectPath, "Uninstall", 0);
+
+  Assert.equal(
+    result.params,
+    "<'a.b.c.desktop'>, <@a{sv} {}>",
+    "Correct desktop entry ID was provided"
+  );
+});
+
+add_task(async function test_uninstall_failure() {
+  await callDbusMethod(portalObjectPath, resetMethod, []);
+  await callDbusMethod(portalObjectPath, clearCallsMethod, []);
+
+  await callDbusMethod(portalObjectPath, addMethodMethod, [
+    portalInterfaceName,
+    "Uninstall",
+    "sa{sv}",
+    "",
+    `raise dbus.exceptions.DBusException("uninstall dbus failed", name="org.mozilla.Error.Mocked")`,
+  ]);
+
+  await Assert.rejects(
+    (async () => ShellService.requestUninstallDynamicLauncher("a.b.c"))(),
+    /.*uninstall dbus failed.*/,
+    "The uninstall request should fail."
+  );
+});

src/zen/tests/mochitests/shell/unit/test_maybeCreateLaunchOnLoginOnFirstRun.js

@@ -1,109 +0,0 @@
-/* Any copyright is dedicated to the Public Domain.
- * https://creativecommons.org/publicdomain/zero/1.0/ */
-
-"use strict";
-
-ChromeUtils.defineESModuleGetters(this, {
-  StartupOSIntegration:
-    "moz-src:///browser/components/shell/StartupOSIntegration.sys.mjs",
-  WindowsLaunchOnLogin: "resource://gre/modules/WindowsLaunchOnLogin.sys.mjs",
-  sinon: "resource://testing-common/Sinon.sys.mjs",
-});
-
-const PREF = "browser.startup.windowsLaunchOnLogin.defaultEnabled";
-
-async function runWith({ isFirstRun, prefValue, approved }) {
-  let sandbox = sinon.createSandbox();
-  let approvedStub = sandbox
-    .stub(WindowsLaunchOnLogin, "getLaunchOnLoginApproved")
-    .resolves(approved);
-  let createStub = sandbox
-    .stub(WindowsLaunchOnLogin, "createLaunchOnLogin")
-    .resolves();
-
-  if (prefValue === null) {
-    Services.prefs.clearUserPref(PREF);
-  } else {
-    Services.prefs.setBoolPref(PREF, prefValue);
-  }
-
-  try {
-    await StartupOSIntegration.maybeCreateLaunchOnLoginOnFirstRun(isFirstRun);
-    return { approvedStub, createStub };
-  } finally {
-    sandbox.restore();
-    Services.prefs.clearUserPref(PREF);
-  }
-}
-
-add_task(async function test_creates_when_all_conditions_true() {
-  let { createStub } = await runWith({
-    isFirstRun: true,
-    prefValue: true,
-    approved: true,
-  });
-  Assert.ok(
-    createStub.calledOnce,
-    "createLaunchOnLogin should be called when isFirstRun, pref, and approval are all true"
-  );
-});
-
-add_task(async function test_skips_when_not_first_run() {
-  let { createStub, approvedStub } = await runWith({
-    isFirstRun: false,
-    prefValue: true,
-    approved: true,
-  });
-  Assert.ok(
-    !createStub.called,
-    "createLaunchOnLogin should not be called when isFirstRun is false"
-  );
-  Assert.ok(
-    !approvedStub.called,
-    "getLaunchOnLoginApproved should be short-circuited when isFirstRun is false"
-  );
-});
-
-add_task(async function test_skips_when_pref_disabled() {
-  let { createStub, approvedStub } = await runWith({
-    isFirstRun: true,
-    prefValue: false,
-    approved: true,
-  });
-  Assert.ok(
-    !createStub.called,
-    "createLaunchOnLogin should not be called when pref is false"
-  );
-  Assert.ok(
-    !approvedStub.called,
-    "getLaunchOnLoginApproved should be short-circuited when pref is false"
-  );
-});
-
-add_task(async function test_skips_when_windows_policy_denies() {
-  let { createStub, approvedStub } = await runWith({
-    isFirstRun: true,
-    prefValue: true,
-    approved: false,
-  });
-  Assert.ok(
-    approvedStub.calledOnce,
-    "getLaunchOnLoginApproved should be consulted when pref and isFirstRun are true"
-  );
-  Assert.ok(
-    !createStub.called,
-    "createLaunchOnLogin should not be called when Windows policy denies"
-  );
-});
-
-add_task(async function test_uses_pref_default_when_unset() {
-  let { createStub } = await runWith({
-    isFirstRun: true,
-    prefValue: null,
-    approved: true,
-  });
-  Assert.ok(
-    createStub.calledOnce,
-    "createLaunchOnLogin should be called when pref is at its built-in default of true"
-  );
-});

src/zen/tests/mochitests/shell/unit/xpcshell.toml

@@ -10,6 +10,21 @@ run-if = [
   "os == 'linux'",
 ]
 
+["test_dynamicLauncher.js"]
+environment = [
+  "XPCSHELL_TEST=1",
+  # The following prevents gsettings from initializing dbus before our mock is
+  # ready.
+  "GSETTINGS_BACKEND=memory",
+]
+run-if = [
+  "os == 'linux'",
+]
+support-files = [
+  "../../../places/tests/browser/favicon-normal16.png",
+]
+tags = ["portal"]
+
 ["test_linuxDesktopEntry.js"]
 run-if = [
   "os == 'linux'",
@@ -20,11 +35,6 @@ run-if = [
   "os == 'mac'",
 ]
 
-["test_maybeCreateLaunchOnLoginOnFirstRun.js"]
-run-if = [
-  "os == 'win'"
-]
-
 ["test_secondaryTileJs.js"]
 run-if = [
   "os == 'win'"

src/zen/tests/moz.build

@@ -20,6 +20,7 @@ BROWSER_CHROME_MANIFESTS += [
     "ub-actions/browser.toml",
     "urlbar/browser.toml",
     "welcome/browser.toml",
+    "window_drag/browser.toml",
     "window_sync/browser.toml",
 ]
 

src/zen/tests/window_drag/browser.toml

@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+[DEFAULT]
+support-files = [
+  "head.js",
+]
+
+["browser_window_drag_basic.js"]

src/zen/tests/window_drag/browser_window_drag_basic.js

@@ -0,0 +1,109 @@
+/* Any copyright is dedicated to the Public Domain.
+   https://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+let gDragStartCount = 0;
+
+add_setup(async function () {
+  const observer = () => gDragStartCount++;
+  Services.obs.addObserver(observer, WINDOW_DRAG_TOPIC);
+  registerCleanupFunction(() => {
+    Services.obs.removeObserver(observer, WINDOW_DRAG_TOPIC);
+  });
+});
+
+add_task(async function test_drag_from_empty_top_area() {
+  await BrowserTestUtils.withNewTab(WINDOW_DRAG_TEST_PAGE, async browser => {
+    await synthesizeContentDrag(browser, 50, 50);
+    await TestUtils.waitForCondition(
+      () => gDragStartCount === 1,
+      "Dragging an empty area in the top region should start a window drag"
+    );
+    is(gDragStartCount, 1, "Exactly one window drag started");
+  });
+});
+
+add_task(async function test_no_drag_on_interactive_target() {
+  await BrowserTestUtils.withNewTab(WINDOW_DRAG_TEST_PAGE, async browser => {
+    // Start the gesture on top of the link. Messages from the same actor
+    // pair are ordered, so the control drag afterwards would arrive later.
+    await BrowserTestUtils.synthesizeMouse(
+      "#link",
+      5,
+      5,
+      { type: "mousedown" },
+      browser
+    );
+    await BrowserTestUtils.synthesizeMouse(
+      "#link",
+      35,
+      15,
+      { type: "mousemove", buttons: 1 },
+      browser
+    );
+    await BrowserTestUtils.synthesizeMouse(
+      "#link",
+      45,
+      20,
+      { type: "mouseup" },
+      browser
+    );
+
+    // Control drag from an eligible area.
+    await synthesizeContentDrag(browser, 50, 50);
+    await TestUtils.waitForCondition(
+      () => gDragStartCount >= 2,
+      "The control drag should start a window drag"
+    );
+    is(
+      gDragStartCount,
+      2,
+      "Dragging a link must not start a window drag (only the control did)"
+    );
+  });
+});
+
+add_task(async function test_no_drag_below_top_region() {
+  await BrowserTestUtils.withNewTab(WINDOW_DRAG_TEST_PAGE, async browser => {
+    const innerHeight = await getContentInnerHeight(browser);
+    await synthesizeContentDrag(browser, 50, Math.floor(innerHeight * 0.6));
+
+    // Control drag from inside the top region.
+    await synthesizeContentDrag(browser, 50, 50);
+    await TestUtils.waitForCondition(
+      () => gDragStartCount >= 3,
+      "The control drag should start a window drag"
+    );
+    is(
+      gDragStartCount,
+      3,
+      "Dragging below the top region must not start a window drag"
+    );
+  });
+});
+
+add_task(async function test_pref_disables_window_drag() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["zen.view.drag-window-from-content", false]],
+  });
+  await BrowserTestUtils.withNewTab(WINDOW_DRAG_TEST_PAGE, async browser => {
+    await synthesizeContentDrag(browser, 50, 50);
+  });
+  await SpecialPowers.popPrefEnv();
+
+  // Control drag with the pref back on, in a fresh tab so the actor is
+  // created again.
+  await BrowserTestUtils.withNewTab(WINDOW_DRAG_TEST_PAGE, async browser => {
+    await synthesizeContentDrag(browser, 50, 50);
+    await TestUtils.waitForCondition(
+      () => gDragStartCount >= 4,
+      "The control drag should start a window drag"
+    );
+    is(
+      gDragStartCount,
+      4,
+      "Dragging with the pref disabled must not start a window drag"
+    );
+  });
+});

src/zen/tests/window_drag/head.js

@@ -0,0 +1,57 @@
+/* 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/. */
+
+"use strict";
+
+const WINDOW_DRAG_TOPIC = "zen-window-drag-started";
+
+const WINDOW_DRAG_TEST_PAGE = `https://example.com/document-builder.sjs?html=${encodeURIComponent(`
+  <!doctype html>
+  <style>
+    body { margin: 0; }
+    #link {
+      position: fixed;
+      top: 20px;
+      left: 300px;
+      width: 100px;
+      height: 30px;
+      display: block;
+    }
+  </style>
+  <a id="link" href="https://example.com/">a link</a>
+`)}`;
+
+/**
+ * Synthesizes a primary-button drag gesture inside the content area,
+ * starting at (x, y) and moving well past the drag threshold.
+ */
+async function synthesizeContentDrag(browser, x, y) {
+  await BrowserTestUtils.synthesizeMouse(
+    null,
+    x,
+    y,
+    { type: "mousedown" },
+    browser
+  );
+  for (let i = 1; i <= 3; i++) {
+    await BrowserTestUtils.synthesizeMouse(
+      null,
+      x + i * 10,
+      y + i * 5,
+      { type: "mousemove", buttons: 1 },
+      browser
+    );
+  }
+  await BrowserTestUtils.synthesizeMouse(
+    null,
+    x + 40,
+    y + 20,
+    { type: "mouseup" },
+    browser
+  );
+}
+
+function getContentInnerHeight(browser) {
+  return SpecialPowers.spawn(browser, [], () => content.innerHeight);
+}

src/zen/window-drag/actors/ZenWindowDragChild.sys.mjs

@@ -0,0 +1,330 @@
+// 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/.
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "dragRegionHeightPercentage",
+  "zen.view.drag-window-from-content.height-percentage",
+  10
+);
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "zenWindowDragUtils",
+  "@mozilla.org/zen/window-drag-utils;1",
+  Ci.nsIZenWindowDragUtils
+);
+
+// Movement below this is considered a click, not a window drag. Fast
+// clicks commonly slide a few pixels (especially on trackpads), and once
+// the native move starts the OS swallows the mouseup — so keep this
+// comfortably above click jitter or clicks in the region get lost.
+const DRAG_START_THRESHOLD_PX = 10;
+
+// Content that drives its own mouse interaction without being
+// interactive HTML content in the spec sense.
+const kAppContentTags = new Set(["audio", "canvas", "video"]);
+
+const kInteractiveRoles = new Set([
+  "button",
+  "checkbox",
+  "combobox",
+  "grid",
+  "link",
+  "listbox",
+  "menu",
+  "menubar",
+  "menuitem",
+  "option",
+  "radio",
+  "scrollbar",
+  "searchbox",
+  "slider",
+  "spinbutton",
+  "switch",
+  "tab",
+  "textbox",
+  "toolbar",
+  "tree",
+  "treegrid",
+]);
+
+// Cursors that signal the page considers the area interactive or draggable.
+const kInteractiveCursors = new Set([
+  "pointer",
+  "grab",
+  "grabbing",
+  "move",
+  "all-scroll",
+  "text",
+  "vertical-text",
+  "cell",
+  "crosshair",
+  "col-resize",
+  "row-resize",
+  "n-resize",
+  "e-resize",
+  "s-resize",
+  "w-resize",
+  "ne-resize",
+  "nw-resize",
+  "se-resize",
+  "sw-resize",
+  "ew-resize",
+  "ns-resize",
+  "nesw-resize",
+  "nwse-resize",
+]);
+
+const kGestureListenerOptions = { mozSystemGroup: true, capture: true };
+
+const kGestureEvents = ["mousemove", "mouseup", "dragstart", "unload"];
+
+export class ZenWindowDragChild extends JSWindowActorChild {
+  #tracking = false;
+  #dragging = false;
+  #startScreenX = 0;
+  #startScreenY = 0;
+
+  handleEvent(event) {
+    // Never let pages spoof the gesture with synthetic events.
+    if (!event.isTrusted) {
+      return;
+    }
+    switch (event.type) {
+      case "mousedown":
+        this.#onMouseDown(event);
+        break;
+      case "mousemove":
+        this.#onMouseMove(event);
+        break;
+      case "mouseup":
+        this.#onMouseUp(event);
+        break;
+      case "dragstart":
+        // The gesture turned out to be a real content drag. Let it win.
+        this.#reset();
+        break;
+      case "unload":
+        this.#reset();
+        break;
+    }
+  }
+
+  get #dragRegionHeight() {
+    const percentage =
+      Math.max(0, Math.min(100, lazy.dragRegionHeightPercentage)) / 100;
+    return this.contentWindow.innerHeight * percentage;
+  }
+
+  #screenPoint(event) {
+    const dpr = this.contentWindow.devicePixelRatio;
+    return {
+      screenX: Math.round(event.screenX * dpr),
+      screenY: Math.round(event.screenY * dpr),
+    };
+  }
+
+  #onMouseDown(event) {
+    if (this.#tracking || this.#dragging) {
+      // The native OS move swallows the mouseup, so a stale gesture may
+      // still be tracked. Recover and evaluate this mousedown normally.
+      this.#reset();
+    }
+    if (
+      event.button !== 0 ||
+      event.buttons !== 1 ||
+      event.detail !== 1 ||
+      event.defaultPrevented ||
+      event.ctrlKey ||
+      event.altKey ||
+      event.shiftKey ||
+      event.metaKey
+    ) {
+      return;
+    }
+    const doc = this.document;
+    if (doc.fullscreenElement || doc.pointerLockElement) {
+      return;
+    }
+    // Only handle events from the top document itself; anything inside an
+    // (i)frame belongs to the page.
+    if (event.composedTarget?.ownerDocument !== doc) {
+      return;
+    }
+    if (event.clientY > this.#dragRegionHeight) {
+      return;
+    }
+    let overContent = true;
+    try {
+      overContent = this.#isEventOverDraggableContent(event);
+    } catch (e) {
+      console.error("ZenWindowDrag: eligibility check failed", e);
+    }
+    if (overContent) {
+      return;
+    }
+    const { screenX, screenY } = this.#screenPoint(event);
+    this.#startScreenX = screenX;
+    this.#startScreenY = screenY;
+    this.#tracking = true;
+    this.#addGestureListeners();
+  }
+
+  #onMouseMove(event) {
+    if (!this.#tracking) {
+      return;
+    }
+    // We missed the mouseup (e.g. the OS consumed it during the native
+    // move, or it happened outside the window).
+    if (!(event.buttons & 1)) {
+      this.#reset();
+      return;
+    }
+    if (this.#dragging) {
+      // Keep the page from extending a text selection under the gesture.
+      event.preventDefault();
+      return;
+    }
+    const point = this.#screenPoint(event);
+    const threshold =
+      DRAG_START_THRESHOLD_PX * this.contentWindow.devicePixelRatio;
+    if (
+      Math.hypot(
+        point.screenX - this.#startScreenX,
+        point.screenY - this.#startScreenY
+      ) < threshold
+    ) {
+      return;
+    }
+    this.#dragging = true;
+    // The mousedown may have moved the caret or started a stray selection.
+    this.contentWindow.getSelection()?.removeAllRanges();
+    // The OS takes over the drag from here.
+    this.sendAsyncMessage("ZenWindowDrag:StartDrag");
+    event.preventDefault();
+  }
+
+  #onMouseUp(event) {
+    if (!this.#tracking || event.button !== 0) {
+      return;
+    }
+    if (this.#dragging) {
+      event.preventDefault();
+      event.preventClickEvent();
+    }
+    this.#reset();
+  }
+
+  #reset() {
+    this.#tracking = false;
+    this.#dragging = false;
+    this.#removeGestureListeners();
+  }
+
+  #addGestureListeners() {
+    const win = this.contentWindow;
+    for (const type of kGestureEvents) {
+      win.addEventListener(type, this, kGestureListenerOptions);
+    }
+  }
+
+  #removeGestureListeners() {
+    const win = this.contentWindow;
+    if (!win) {
+      return;
+    }
+    for (const type of kGestureEvents) {
+      win.removeEventListener(type, this, kGestureListenerOptions);
+    }
+  }
+
+  /**
+   * Returns true if starting a window drag here would fight with content
+   * that the page wants to be clickable, draggable or selectable.
+   *
+   * @param {MouseEvent} event
+   */
+  #isEventOverDraggableContent(event) {
+    // Scrollbars and other native anonymous parts only dispatch to the
+    // system group, which is us. Never treat those as a window drag.
+    if (event.originalTarget?.isNativeAnonymous) {
+      return true;
+    }
+    let target = event.composedTarget;
+    if (target?.nodeType === Node.TEXT_NODE) {
+      target = target.parentElement;
+    }
+    if (!target || target.nodeType !== Node.ELEMENT_NODE) {
+      return true;
+    }
+    for (let node = target; node; node = node.flattenedTreeParentNode) {
+      if (node.nodeType !== Node.ELEMENT_NODE) {
+        continue;
+      }
+      if (this.#isInteractiveElement(node)) {
+        return true;
+      }
+    }
+    return (
+      this.#hasInteractiveCursor(target) || this.#isOverSelectableText(event)
+    );
+  }
+
+  /**
+   * A drag starting over selectable text should select it, not move the
+   * window. rangeParent is the caret position Gecko computed for the
+   * event, so this also covers empty space on the same line, where
+   * dragging extends a selection.
+   *
+   * @param {MouseEvent} event
+   */
+  #isOverSelectableText(event) {
+    const node = event.rangeParent;
+    if (node?.nodeType !== Node.TEXT_NODE) {
+      return false;
+    }
+    const parent = node.parentElement;
+    return (
+      !parent ||
+      this.contentWindow.getComputedStyle(parent).userSelect !== "none"
+    );
+  }
+
+  #isInteractiveElement(element) {
+    // Gecko's own notion of interactive, editable or draggable content.
+    if (lazy.zenWindowDragUtils.isInteractiveContent(element)) {
+      return true;
+    }
+    if (kAppContentTags.has(element.localName)) {
+      return true;
+    }
+    // Declarative signals the engine check doesn't cover: ARIA widget
+    // roles and explicit tab stops.
+    if (
+      element.tabIndex >= 0 &&
+      element !== this.document.body &&
+      element !== this.document.documentElement
+    ) {
+      return true;
+    }
+    const role = element.getAttribute?.("role");
+    return !!role && kInteractiveRoles.has(role.toLowerCase());
+  }
+
+  #hasInteractiveCursor(element) {
+    const style = element.ownerGlobal?.getComputedStyle(element);
+    if (!style) {
+      return false;
+    }
+    // The keyword is always the last component of the computed value.
+    // Don't split on "," as url() cursor images may contain commas.
+    const cursor = style.cursor.match(/[a-z-]+$/)?.[0];
+    return kInteractiveCursors.has(cursor);
+  }
+}

src/zen/window-drag/actors/ZenWindowDragParent.sys.mjs

@@ -0,0 +1,33 @@
+// 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/.
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "zenDragAndDropService",
+  "@mozilla.org/zen/drag-and-drop;1",
+  Ci.nsIZenDragAndDrop
+);
+
+export class ZenWindowDragParent extends JSWindowActorParent {
+  receiveMessage(message) {
+    if (message.name !== "ZenWindowDrag:StartDrag") {
+      return;
+    }
+    const win = this.browsingContext.topChromeWindow;
+    if (!win || win.closed || win.windowState === win.STATE_FULLSCREEN) {
+      return;
+    }
+    if (Cu.isInAutomation) {
+      // Tests can't exercise a real OS drag session; let them observe the
+      // decision instead.
+      Services.obs.notifyObservers(win, "zen-window-drag-started");
+      return;
+    }
+    lazy.zenDragAndDropService.beginNativeWindowMove(win);
+  }
+}

src/zen/window-drag/components.conf

@@ -0,0 +1,13 @@
+# 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/.
+
+Classes = [
+    {
+        'cid': '{13df8214-70b4-4d7b-af8c-86081cbc5801}',
+        'interfaces': ['nsIZenWindowDragUtils'],
+        'contract_ids': ['@mozilla.org/zen/window-drag-utils;1'],
+        'type': 'zen::nsZenWindowDragUtils',
+        'headers': ['mozilla/nsZenWindowDragUtils.h'],
+    },
+]

src/zen/window-drag/moz.build

@@ -0,0 +1,27 @@
+# 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/.
+
+FINAL_TARGET_FILES.actors += [
+    "actors/ZenWindowDragChild.sys.mjs",
+    "actors/ZenWindowDragParent.sys.mjs",
+]
+
+XPIDL_SOURCES += [
+    "nsIZenWindowDragUtils.idl",
+]
+
+EXPORTS.mozilla += [
+    "nsZenWindowDragUtils.h",
+]
+
+SOURCES += [
+    "nsZenWindowDragUtils.cpp",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+FINAL_LIBRARY = "xul"
+XPIDL_MODULE = "zen_window_drag"

src/zen/window-drag/nsIZenWindowDragUtils.idl

@@ -0,0 +1,23 @@
+/* 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/. */
+
+#include "nsISupports.idl"
+
+webidl Node;
+
+/**
+ * @brief Utilities for deciding when a content-area gesture may move
+ * the window.
+ */
+[scriptable, uuid(595ba6e8-abe2-4619-acad-cf492306f608)]
+interface nsIZenWindowDragUtils : nsISupports {
+  /**
+   * @brief Whether the node is content the page expects the user to
+   * interact with: interactive HTML content (links, form controls,
+   * etc.), editable content, or content that can be dragged
+   * (draggable attribute, links and loaded images).
+   * @param node The node to check.
+   */
+  boolean isInteractiveContent(in Node node);
+};

src/zen/window-drag/nsZenWindowDragUtils.cpp

@@ -0,0 +1,33 @@
+/* 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/. */
+
+#include "nsZenWindowDragUtils.h"
+
+#include "mozilla/dom/Element.h"
+#include "nsContentUtils.h"
+#include "nsIContent.h"
+
+namespace zen {
+
+NS_IMPL_ISUPPORTS(nsZenWindowDragUtils, nsIZenWindowDragUtils)
+
+NS_IMETHODIMP
+nsZenWindowDragUtils::IsInteractiveContent(nsINode* aNode, bool* aResult) {
+  *aResult = false;
+  NS_ENSURE_ARG_POINTER(aNode);
+
+  nsIContent* content = nsIContent::FromNode(aNode);
+  if (!content) {
+    return NS_OK;
+  }
+  if (content->IsEditable() || nsContentUtils::ContentIsDraggable(content)) {
+    *aResult = true;
+    return NS_OK;
+  }
+  mozilla::dom::Element* element = mozilla::dom::Element::FromNode(content);
+  *aResult = element && element->IsInteractiveHTMLContent();
+  return NS_OK;
+}
+
+}  // namespace zen

src/zen/window-drag/nsZenWindowDragUtils.h

@@ -0,0 +1,27 @@
+/* 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/. */
+
+#ifndef zen_nsZenWindowDragUtils_h_
+#define zen_nsZenWindowDragUtils_h_
+
+#include "nsIZenWindowDragUtils.h"
+
+#define ZEN_WINDOW_DRAG_UTILS_CONTRACTID "@mozilla.org/zen/window-drag-utils;1"
+
+namespace zen {
+
+class nsZenWindowDragUtils final : public nsIZenWindowDragUtils {
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIZENWINDOWDRAGUTILS
+
+ public:
+  nsZenWindowDragUtils() = default;
+
+ private:
+  ~nsZenWindowDragUtils() = default;
+};
+
+}  // namespace zen
+
+#endif

surfer.json

@@ -5,8 +5,8 @@
   "binaryName": "zen",
   "version": {
     "product": "firefox",
-    "version": "153.0",
-    "candidate": "153.0",
+    "version": "153.0.1",
+    "candidate": "153.0.1",
     "candidateBuild": 1
   },
   "buildOptions": {
@@ -20,7 +20,7 @@
       "brandShortName": "Zen",
       "brandFullName": "Zen Browser",
       "release": {
-        "displayVersion": "1.21.9b",
+        "displayVersion": "1.21.10b",
         "github": {
           "repo": "zen-browser/desktop"
         },