From a4727252094d903b6ccbe455bf5f0b9e885d8114 Mon Sep 17 00:00:00 2001
From: Andrzej Martyna <andrzej.martyna@gmail.com>
Date: Tue, 30 Dec 2025 09:06:57 +0100
Subject: [PATCH] Resolved: Thread-safety concern: _browserWindowsTracked
 modified without synchronization.

---
 .../Tabs/README.md                            |  3 +-
 .../Tabs/TabsTracker.cs                       | 38 +++++++++++++++----
 .../Tabs/TabsWalker.cs                        |  2 +-
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/README.md b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/README.md
index fa41cf10e..fb561d7ed 100644
--- a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/README.md
+++ b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/README.md
@@ -23,7 +23,8 @@ Next, each time the bookmark is triggered again, it just switches to the existin
 
 The extension bases on RuntimeId of AutomationElement from Microsoft UI Automation.  
 This is a weak spot as browsers are used to regenerate internal structures and even reuse RuntimeId.  
-It **rarely** happens that a bookmark activates a wrong tab.  
+Therefore it happens that a bookmark activates a wrong tab.  
+The most common case is while user opens several tabs one after the other quickly.  
 Still **"just take me to THIS place in milliseconds"** works almost all of the time so it brings so much value that it is worthwhile to accept the fact it fails sometimes.  
 
 The quickest workaround is:  
diff --git a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsTracker.cs b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsTracker.cs
index c0e3fd97b..588bc44c5 100644
--- a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsTracker.cs
+++ b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsTracker.cs
@@ -84,7 +84,12 @@ public class TabsTracker : IDisposable
 
     public void Dispose()
     {
-        var windowsToUnsubscribe = _browserWindowsTracked.ToList();
+        List<AutomationElement> windowsToUnsubscribe;
+        lock (_sync)
+        {
+            windowsToUnsubscribe = _browserWindowsTracked.ToList();
+        }
+
         foreach (var wnd in windowsToUnsubscribe)
         {
             UnsubscribeStructureChangedForWindow(wnd);
@@ -210,14 +215,22 @@ public class TabsTracker : IDisposable
             //    break;
             case StructureChangeType.ChildRemoved:
             case StructureChangeType.ChildrenBulkRemoved:
-                foreach (var window in _browserWindowsTracked)
+                AutomationElement foundWindow = null;
+                lock (_sync)
                 {
-                    var windowRuntimeId = TabsCache.RuntimeIdToKey(window);
-                    if (windowRuntimeId != null && eventRuntimeId.StartsWith(windowRuntimeId))
+                    foreach (var window in _browserWindowsTracked)
                     {
-                        _walker.RescanTabsForContainer(window);
+                        var windowRuntimeId = TabsCache.RuntimeIdToKey(window);
+                        if (windowRuntimeId != null && eventRuntimeId.StartsWith(windowRuntimeId))
+                        {
+                            foundWindow = window;
+                        }
                     }
                 }
+                if (foundWindow != null)
+                {
+                    _walker.RescanTabsForContainer(foundWindow);
+                }
                 break;
         }
     }
@@ -232,11 +245,16 @@ public class TabsTracker : IDisposable
 
     private void UnsubscribeStructureChangedForWindow(AutomationElement wnd)
     {
-        if (_browserWindowsTracked.Contains(wnd))
+        bool contains = false;
+        lock (_sync)
+        {
+            contains = _browserWindowsTracked.Contains(wnd);
+            _browserWindowsTracked.Remove(wnd);
+        }
+        if (contains)
         {
             Context.API.LogDebug(ClassName, "Unsubscribe window from StructureChanged events");
             Automation.RemoveStructureChangedEventHandler(wnd, OnStructureChanged);
-            _browserWindowsTracked.Remove(wnd);
             _walker?.RemoveAllTabs(wnd);
         }
     }
@@ -254,6 +272,10 @@ public class TabsTracker : IDisposable
 
         Automation.AddStructureChangedEventHandler(rootElement, TreeScope.Subtree, OnStructureChanged);
         Automation.AddAutomationEventHandler(WindowPattern.WindowClosedEvent, rootElement, TreeScope.Subtree, OnWindowClosed);
-        _browserWindowsTracked.Add(rootElement);
+
+        lock (_sync)
+        {
+            _browserWindowsTracked.Add(rootElement);
+        }
     }
 }
diff --git a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsWalker.cs b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsWalker.cs
index c0e32a3f2..f73297eec 100644
--- a/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsWalker.cs
+++ b/Plugins/Flow.Launcher.Plugin.BrowserBookmark/Tabs/TabsWalker.cs
@@ -33,7 +33,7 @@ internal class TabsWalker
                 continue;
             }
 
-            // on Chrome, there are kind of technical tabs that should be ignored
+            // There are kind of technical tabs that should be ignored
             var className = tab.Current.ClassName;
             if (className.Contains("bolt-tab", StringComparison.OrdinalIgnoreCase))
             {