Workaround dev tools issue

samples/ControlCatalog/App.xaml.cs

@@ -78,9 +78,12 @@ namespace ControlCatalog
 
         public override void Initialize()
         {
-            Styles.Insert(0, Fluent);
+            Styles.Insert(0, DefaultLight);
-            Styles.Insert(1, ColorPickerFluent);
+            Styles.Insert(1, ColorPickerDefault);
-            Styles.Insert(2, DataGridFluent);
+            Styles.Insert(2, DataGridDefault);
+            //Styles.Insert(0, Fluent);
+            //Styles.Insert(1, ColorPickerFluent);
+            //Styles.Insert(2, DataGridFluent);
             AvaloniaXamlLoader.Load(this);
         }
 

src/Avalonia.Diagnostics/Diagnostics/Views/MainWindow.xaml

@@ -4,7 +4,8 @@
         xmlns:diag="clr-namespace:Avalonia.Diagnostics"
         xmlns:default="using:Avalonia.Themes.Default"
         Title="Avalonia DevTools"
-        x:Class="Avalonia.Diagnostics.Views.MainWindow">
+        x:Class="Avalonia.Diagnostics.Views.MainWindow"
+        Theme="{StaticResource {x:Type Window}}">
   <Window.DataTemplates>
     <diag:ViewLocator/>
   </Window.DataTemplates>