diff --git a/demo/Ursa.Demo/Dialogs/CustomDemoDialog.axaml.cs b/demo/Ursa.Demo/Dialogs/CustomDemoDialog.axaml.cs
index c8353aa..7e5cd07 100644
--- a/demo/Ursa.Demo/Dialogs/CustomDemoDialog.axaml.cs
+++ b/demo/Ursa.Demo/Dialogs/CustomDemoDialog.axaml.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Notifications;
@@ -23,24 +24,14 @@ public partial class CustomDemoDialog : UserControl
         base.OnAttachedToVisualTree(e);
         _viewModel = this.DataContext as CustomDemoDialogViewModel;
         var visualLayerManager = this.FindAncestorOfType<VisualLayerManager>();
-        if (visualLayerManager is not null && _viewModel is not null)
-        {
-            _viewModel.NotificationManager = new WindowNotificationManager(visualLayerManager) { MaxItems = 3 };
-            _viewModel.ToastManager = new WindowToastManager(visualLayerManager) { MaxItems = 3 };
-        }
-
-        WindowNotificationManager.TryGetNotificationManager(visualLayerManager, out var manager);
-        if (manager is not null && _viewModel is not null)
-        {
-            Console.WriteLine(ReferenceEquals(_viewModel.NotificationManager, manager));
-            manager.Position = NotificationPosition.TopCenter;
-        }
-    }
-
-    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
-    {
-        base.OnDetachedFromVisualTree(e);
-        _viewModel?.NotificationManager?.Uninstall();
-        _viewModel?.ToastManager?.Uninstall();
+        if (_viewModel == null) return;
+        _viewModel.NotificationManager =
+            WindowNotificationManager.TryGetNotificationManager(visualLayerManager, out var notificationManager)
+                ? notificationManager
+                : new WindowNotificationManager(visualLayerManager) { MaxItems = 3 };
+        _viewModel.ToastManager = WindowToastManager.TryGetToastManager(visualLayerManager, out var toastManager)
+            ? toastManager
+            : new WindowToastManager(visualLayerManager) { MaxItems = 3 };
+        Debug.Assert(WindowNotificationManager.TryGetNotificationManager(visualLayerManager, out _));
     }
 }
\ No newline at end of file