RenderTransformOrigin should also look to Propertygrid changes

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/RenderTransformOriginExtension.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Text;
 using ICSharpCode.WpfDesign.Adorners;
@@ -55,14 +56,13 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 			var pointAbsNew = pointAbs + new Vector(e.HorizontalChange, e.VerticalChange);
 			var pRel = adornerPanel.AbsoluteToRelative(pointAbsNew);
 			
-			AdornerPanel.SetPlacement(renderTransformOriginThumb,
-			                          new RelativePlacement(HorizontalAlignment.Left, VerticalAlignment.Top){ XRelativeToContentWidth = pRel.X, YRelativeToContentHeight = pRel.Y });
-			
 			this.ExtendedItem.Properties.GetProperty(FrameworkElement.RenderTransformOriginProperty).SetValue(new Point(Math.Round(pRel.X, 4), Math.Round(pRel.Y, 4)));
 		}
 		
 		Point renderTransformOrigin = new Point(0.5, 0.5);
 		
+		DependencyPropertyDescriptor renderTransformOriginPropertyDescriptor;
+		
 		protected override void OnInitialized()
 		{
 			base.OnInitialized();
@@ -75,6 +75,20 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 			
 			AdornerPanel.SetPlacement(renderTransformOriginThumb,
 			                          new RelativePlacement(HorizontalAlignment.Left, VerticalAlignment.Top){XRelativeToContentWidth = renderTransformOrigin.X, YRelativeToContentHeight = renderTransformOrigin.Y});
+			
+			renderTransformOriginPropertyDescriptor = DependencyPropertyDescriptor.FromProperty(FrameworkElement.RenderTransformOriginProperty, typeof(FrameworkElement));
+			renderTransformOriginPropertyDescriptor.AddValueChanged(this.ExtendedItem.Component, OnRenderTransformOriginPropertyChanged);
+		}
+		
+		private void OnRenderTransformOriginPropertyChanged(object sender, EventArgs e)
+		{
+			var pRel = renderTransformOrigin;
+			if (this.ExtendedItem.Properties.GetProperty(FrameworkElement.RenderTransformOriginProperty).IsSet)
+				pRel = (Point)this.ExtendedItem.Properties.GetProperty(FrameworkElement.RenderTransformOriginProperty).ValueOnInstance;
+						
+			AdornerPanel.SetPlacement(renderTransformOriginThumb,
+			                          new RelativePlacement(HorizontalAlignment.Left, VerticalAlignment.Top){ XRelativeToContentWidth = pRel.X, YRelativeToContentHeight = pRel.Y });
+			
 		}
 		
 		void OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
@@ -82,6 +96,8 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 		
 		protected override void OnRemove()
 		{
+			renderTransformOriginPropertyDescriptor.RemoveValueChanged(this.ExtendedItem.Component, OnRenderTransformOriginPropertyChanged);
+			
 			base.OnRemove();
 		}
 	}