Update MainWindow.axaml.cs

samples/ColorBlenderAvalonia/MainWindow.axaml.cs

@@ -1,4 +1,5 @@
-using Avalonia.Controls;
+using Avalonia;
+using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
 
 namespace ColorBlenderAvalonia
@@ -8,6 +9,9 @@ namespace ColorBlenderAvalonia
         public MainWindow()
         {
             this.InitializeComponent();
+#if DEBUG
+            this.AttachDevTools();
+#endif
         }
 
         private void InitializeComponent()