diff --git a/demo/Ursa.Demo/Pages/NotificationDemo.axaml.cs b/demo/Ursa.Demo/Pages/NotificationDemo.axaml.cs
index ccdb5d0..53f5e65 100644
--- a/demo/Ursa.Demo/Pages/NotificationDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NotificationDemo.axaml.cs
@@ -20,11 +20,10 @@ public partial class NotificationDemo : UserControl
     {
         base.OnAttachedToVisualTree(e);
         var topLevel = TopLevel.GetTopLevel(this);
-
-        WindowNotificationManager.TryGetNotificationManager(topLevel, out var manager);
-        if (manager is not null)
-        {
-            _viewModel.NotificationManager = manager;
-        }
+        if (topLevel is null)
+            return;
+        _viewModel.NotificationManager = WindowNotificationManager.TryGetNotificationManager(topLevel, out var manager)
+            ? manager
+            : new WindowNotificationManager(topLevel);
     }
 }
\ No newline at end of file
diff --git a/demo/Ursa.Demo/Views/MainView.axaml.cs b/demo/Ursa.Demo/Views/MainView.axaml.cs
index c7353e1..9cb2b0d 100644
--- a/demo/Ursa.Demo/Views/MainView.axaml.cs
+++ b/demo/Ursa.Demo/Views/MainView.axaml.cs
@@ -19,10 +19,10 @@ public partial class MainView : UserControl
         base.OnAttachedToVisualTree(e);
         _viewModel = DataContext as MainViewViewModel;
         var topLevel = TopLevel.GetTopLevel(this);
-        WindowNotificationManager.TryGetNotificationManager(topLevel, out var manager);
-        if (manager is not null && _viewModel is not null)
-        {
-            _viewModel.NotificationManager = manager;
-        }
+        if (topLevel is null || _viewModel is null)
+            return;
+        _viewModel.NotificationManager = WindowNotificationManager.TryGetNotificationManager(topLevel, out var manager)
+            ? manager
+            : new WindowNotificationManager(topLevel);
     }
 }
\ No newline at end of file