Fix: subscribe to ItemsChanged before fetching items to avoid missing early events

Agent-Logs-Url: https://github.com/microsoft/PowerToys/sessions/3f380bd3-a56a-4708-80ef-3e7d534c4f6f

Co-authored-by: MuyuanMS <116717757+MuyuanMS@users.noreply.github.com>

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ContentPageViewModel.cs

@@ -129,8 +129,8 @@ public partial class ContentPageViewModel : PageViewModel, ICommandBarContext
 
         UpdateDetails();
 
-        FetchContent();
         model.ItemsChanged += Model_ItemsChanged;
+        FetchContent();
 
         DoOnUiThread(
         () =>

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ContentTreeViewModel.cs

@@ -44,9 +44,9 @@ public partial class ContentTreeViewModel(ITreeContent _tree, WeakReference<IPag
             UpdateProperty(nameof(Root));
         }
 
-        FetchContent();
         model.PropChanged += Model_PropChanged;
         model.ItemsChanged += Model_ItemsChanged;
+        FetchContent();
     }
 
     // Theoretically, we should unify this with the one in CommandPalettePageViewModelFactory

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Dock/DockBandViewModel.cs

@@ -209,8 +209,8 @@ public sealed partial class DockBandViewModel : ExtensionObjectViewModel
         var list = command.Model.Unsafe as IListPage;
         if (list is not null)
         {
-            InitializeFromList(list);
             list.ItemsChanged += HandleItemsChanged;
+            InitializeFromList(list);
         }
         else
         {

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ListViewModel.cs

@@ -957,8 +957,8 @@ public partial class ListViewModel : PageViewModel, IDisposable
         Filters?.InitializeProperties();
         UpdateProperty(nameof(Filters));
 
-        FetchItems(true);
         model.ItemsChanged += Model_ItemsChanged;
+        FetchItems(true);
     }
 
     private static IGridPropertiesViewModel? LoadGridPropertiesViewModel(IGridProperties? gridProperties)

src/modules/launcher/PowerLauncher/App.xaml.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.ComponentModel;
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
@@ -121,18 +120,7 @@ namespace PowerLauncher
                     });
                 }
 
-                try
-                {
-                    application.Run();
-                }
-                catch (Win32Exception ex) when (ex.NativeErrorCode == 1400)
-                {
-                    // ERROR_INVALID_WINDOW_HANDLE (1400) can be thrown by the WPF dispatcher
-                    // after a fast user switch, when its internal message-only window handle
-                    // becomes invalid upon session restoration. Exit gracefully so the
-                    // PowerToys runner can restart PowerLauncher.
-                    Log.Warn($"PowerToys Run exiting due to invalid window handle after user switch: {ex.Message}", typeof(App));
-                }
+                application.Run();
             }
         }