More fixes

src/App.axaml.cs

@@ -100,6 +100,8 @@ namespace AvaloniaCoreRTDemo
 
                 desktop.MainWindow = newWindow;
                 this.DataContext = newWindow.DataContext;
+
+                oldWindow.Hide();
                 newWindow.Show();
                 oldWindow.Close();
             }

src/Windows/MainWindow.axaml.cs

@@ -37,6 +37,7 @@ namespace AvaloniaCoreRTDemo.Windows
             if (window is not null)
             {
                 this.MainControl.Reload(window.Model);
+                this.WindowStartupLocation = WindowStartupLocation.Manual;
                 this.WindowState = window.State;
                 this.Position = window.Position;
                 this.FrameSize = window.FrameSize;