Added WantsLayer property

src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs

@@ -367,6 +367,8 @@ namespace Avalonia.Rendering.SceneGraph
 
         private static bool ShouldStartLayer(IVisual visual)
         {
+            if (visual.WantsLayer)
+                return true;
             var o = visual as IAvaloniaObject;
             return visual.VisualChildren.Count > 0 &&
                 o != null &&

src/Avalonia.Visuals/Visual.cs

@@ -90,10 +90,18 @@ namespace Avalonia
         public static readonly StyledProperty<int> ZIndexProperty =
             AvaloniaProperty.Register<Visual, int>(nameof(ZIndex));
 
+        /// <summary>
+        /// Defines the <see cref="WantsLayer"/> property.
+        /// </summary>
+        public static readonly DirectProperty<Visual, bool> WantsLayerProperty =
+            AvaloniaProperty.RegisterDirect<Visual, bool>("WantsLayer", o => o._wantsLayer,
+                (o, v) => o._wantsLayer = v);
+
         private Rect _bounds;
         private TransformedBounds? _transformedBounds;
         private IRenderRoot _visualRoot;
         private IVisual _visualParent;
+        private bool _wantsLayer;
 
         /// <summary>
         /// Initializes static members of the <see cref="Visual"/> class.
@@ -105,7 +113,8 @@ namespace Avalonia
                 ClipProperty,
                 ClipToBoundsProperty,
                 IsVisibleProperty,
-                OpacityProperty);
+                OpacityProperty,
+                WantsLayerProperty);
             RenderTransformProperty.Changed.Subscribe(RenderTransformChanged);
         }
 
@@ -239,6 +248,15 @@ namespace Avalonia
             private set;
         }
 
+        /// <summary>
+        /// Allows to explicitly force a rendering layer for a particular visual. Use with caution.
+        /// </summary>
+        public bool WantsLayer
+        {
+            get => GetValue(WantsLayerProperty);
+            set => SetValue(WantsLayerProperty, value);
+        }
+
         /// <summary>
         /// Gets the root of the visual tree, if the control is attached to a visual tree.
         /// </summary>

src/Avalonia.Visuals/VisualTree/IVisual.cs

@@ -127,5 +127,10 @@ namespace Avalonia.VisualTree
         /// common ancestor.
         /// </returns>
         Matrix? TransformToVisual(IVisual visual);
+        
+        /// <summary>
+        /// Allows to explicitly force a rendering layer for a particular visual. Use with caution.
+        /// </summary>
+        bool WantsLayer { get; }
     }
 }