Apply own control theme before templated parent's.

src/Avalonia.Base/Styling/Styler.cs

@@ -8,14 +8,14 @@ namespace Avalonia.Styling
         {
             _ = target ?? throw new ArgumentNullException(nameof(target));
 
-            // If the control has a themed templated parent then first apply the styles from
-            // the templated parent theme.
+            // Apply the control theme.
+            target.GetEffectiveTheme()?.TryAttach(target, target);
+
+            // If the control has a themed templated parent then apply the styles from the
+            // templated parent theme.
             if (target.TemplatedParent is IStyleable styleableParent)
                 styleableParent.GetEffectiveTheme()?.TryAttach(target, styleableParent);
 
-            // Next apply the control theme.
-            target.GetEffectiveTheme()?.TryAttach(target, target);
-
             // Apply styles from the rest of the tree.
             if (target is IStyleHost styleHost)
                 ApplyStyles(target, styleHost);