Address review: handle NavigationFailed gracefully without rethrowing

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/settings-ui/Settings.UI/ViewModels/PageViewModelBase.cs

@@ -6,6 +6,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.PowerToys.Settings.UI.Helpers;
 using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.PowerToys.Settings.UI.Library.Helpers;
@@ -70,8 +71,18 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
                 }
             }
 
-            var dispatcherQueue = App.GetSettingsWindow()?.DispatcherQueue;
-            dispatcherQueue?.TryEnqueue(Microsoft.UI.Dispatching.DispatcherQueuePriority.Normal, UpdateConflictProperties);
+            _ = Task.Run(() =>
+            {
+                try
+                {
+                    var settingsWindow = App.GetSettingsWindow();
+                    settingsWindow.DispatcherQueue.TryEnqueue(Microsoft.UI.Dispatching.DispatcherQueuePriority.Normal, UpdateConflictProperties);
+                }
+                catch
+                {
+                    UpdateConflictProperties();
+                }
+            });
         }
 
         public virtual Dictionary<string, HotkeySettings[]> GetAllHotkeySettings()

src/settings-ui/Settings.UI/ViewModels/ShellViewModel.cs

@@ -9,6 +9,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using System.Windows.Input;
 
+using ManagedCommon;
 using Microsoft.PowerToys.Settings.UI.Helpers;
 using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.PowerToys.Settings.UI.Library.Helpers;
@@ -135,7 +136,18 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
 
         private void Frame_NavigationFailed(object sender, NavigationFailedEventArgs e)
         {
-            throw e.Exception;
+            var sourcePage = e.SourcePageType?.FullName ?? "<unknown>";
+
+            if (e.Exception is null)
+            {
+                Logger.LogWarning($"Navigation to '{sourcePage}' failed without an exception.");
+            }
+            else
+            {
+                Logger.LogError($"Navigation to '{sourcePage}' failed.", e.Exception);
+            }
+
+            e.Handled = true;
         }
 
         private void Frame_Navigated(object sender, NavigationEventArgs e)

src/settings-ui/Settings.UI/ViewModels/ShortcutConflictViewModel.cs

@@ -12,8 +12,8 @@ using System.Reflection;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using System.Text.Json.Serialization.Metadata;
+using System.Windows.Threading;
 using ManagedCommon;
-using Microsoft.UI.Dispatching;
 using Microsoft.PowerToys.Settings.UI.Helpers;
 using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.PowerToys.Settings.UI.Library.Helpers;
@@ -29,7 +29,7 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
     {
         private readonly SettingsFactory _settingsFactory;
         private readonly Func<string, int> _ipcMSGCallBackFunc;
-        private readonly DispatcherQueue _dispatcherQueue;
+        private readonly Dispatcher _dispatcher;
 
         private bool _disposed;
         private AllHotkeyConflictsData _conflictsData = new();
@@ -41,7 +41,7 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
             ISettingsRepository<GeneralSettings> settingsRepository,
             Func<string, int> ipcMSGCallBackFunc)
         {
-            _dispatcherQueue = DispatcherQueue.GetForCurrentThread();
+            _dispatcher = Dispatcher.CurrentDispatcher;
             _ipcMSGCallBackFunc = ipcMSGCallBackFunc ?? throw new ArgumentNullException(nameof(ipcMSGCallBackFunc));
             resourceLoader = ResourceLoaderInstance.ResourceLoader;
 
@@ -123,7 +123,7 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
 
         protected override void OnConflictsUpdated(object sender, AllHotkeyConflictsEventArgs e)
         {
-            _dispatcherQueue?.TryEnqueue(() =>
+            _dispatcher.BeginInvoke(() =>
             {
                 ConflictsData = e.Conflicts ?? new AllHotkeyConflictsData();
             });