Invalidate controls when brush changed.

src/Avalonia.Controls/Border.cs

@@ -43,8 +43,9 @@ namespace Avalonia.Controls
         /// </summary>
         static Border()
         {
-            AffectsRender(BackgroundProperty, BorderBrushProperty, BorderThicknessProperty, CornerRadiusProperty);
+            AffectsRender(BorderThicknessProperty, CornerRadiusProperty);
             AffectsMeasure(BorderThicknessProperty);
+            BrushAffectsRender<Border>(BackgroundProperty, BorderBrushProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/Panel.cs

@@ -30,6 +30,7 @@ namespace Avalonia.Controls
         /// </summary>
         static Panel()
         {
+            BrushAffectsRender<Panel>(BackgroundProperty);
             ClipToBoundsProperty.OverrideDefaultValue<Panel>(true);
         }
 

src/Avalonia.Controls/Presenters/ContentPresenter.cs

@@ -90,8 +90,9 @@ namespace Avalonia.Controls.Presenters
         /// </summary>
         static ContentPresenter()
         {
-            AffectsRender(BackgroundProperty, BorderBrushProperty, BorderThicknessProperty, CornerRadiusProperty);
+            AffectsRender(BorderThicknessProperty, CornerRadiusProperty);
             AffectsMeasure(BorderThicknessProperty, PaddingProperty);
+            BrushAffectsRender<ContentPresenter>(BackgroundProperty, BorderBrushProperty);
             ContentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
             ContentTemplateProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
             TemplatedParentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.TemplatedParentChanged);

src/Avalonia.Controls/Shapes/Shape.cs

@@ -30,11 +30,11 @@ namespace Avalonia.Controls.Shapes
         private Geometry _renderedGeometry;
         bool _calculateTransformOnArrange = false;
 
-
         static Shape()
         {
             AffectsMeasure(StretchProperty, StrokeThicknessProperty);
-            AffectsRender(FillProperty, StrokeProperty, StrokeDashArrayProperty);
+            AffectsRender(StrokeDashArrayProperty);
+            BrushAffectsRender<Shape>(FillProperty, StrokeProperty);
         }
 
         public Geometry DefiningGeometry

src/Avalonia.Controls/TextBlock.cs

@@ -99,10 +99,10 @@ namespace Avalonia.Controls
         static TextBlock()
         {
             ClipToBoundsProperty.OverrideDefaultValue<TextBlock>(true);
-            AffectsRender(ForegroundProperty);
             AffectsRender(FontWeightProperty);
             AffectsRender(FontSizeProperty);
             AffectsRender(FontStyleProperty);
+            BrushAffectsRender<TextBlock>(BackgroundProperty, ForegroundProperty);
         }
 
         /// <summary>

src/Avalonia.Visuals/Visual.cs

@@ -328,6 +328,44 @@ namespace Avalonia
             }
         }
 
+        /// <summary>
+        /// Indicates that a brush property change should cause <see cref="InvalidateVisual"/> to be
+        /// called.
+        /// </summary>
+        /// <param name="properties">The properties.</param>
+        /// <remarks>
+        /// This method should be called in a control's static constructor with each property
+        /// on the control which when changed should cause a redraw. It not only triggers an
+        /// invalidation when the property itself changes, but also when the brush raises
+        /// the <see cref="IMutableBrush.Changed"/> event.
+        /// </remarks>
+        protected static void BrushAffectsRender<T>(params AvaloniaProperty<IBrush>[] properties)
+            where T : Visual
+        {
+            void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            {
+                if (e.Sender is T sender)
+                {
+                    if (e.OldValue is IMutableBrush oldValue)
+                    {
+                        oldValue.Changed -= sender.BrushChanged;
+                    }
+
+                    if (e.NewValue is IMutableBrush newValue)
+                    {
+                        newValue.Changed += sender.BrushChanged;
+                    }
+
+                    sender.InvalidateVisual();
+                }
+            }
+
+            foreach (var property in properties)
+            {
+                property.Changed.Subscribe(Invalidate);
+            }
+        }
+
         /// <summary>
         /// Calls the <see cref="OnAttachedToVisualTree(VisualTreeAttachmentEventArgs)"/> method 
         /// for this control and all of its visual descendants.
@@ -530,6 +568,8 @@ namespace Avalonia
             OnVisualParentChanged(old, value);
         }
 
+        private void BrushChanged(object sender, EventArgs e) => InvalidateVisual();
+
         /// <summary>
         /// Called when the <see cref="VisualChildren"/> collection changes.
         /// </summary>