Better fix in Collection Support for Resource Dictionarys.

They way it was now, there could be 2 Styles with the same Type and then we get the "same Key already added" Exception!

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.XamlDom/Project/CollectionSupport.cs

@@ -68,12 +68,10 @@ namespace ICSharpCode.WpfDesign.XamlDom
 			} else if (collectionInstance is ResourceDictionary) {
 				object val = newElement.GetValueFor(null);
 				object key = newElement is XamlObject ? ((XamlObject)newElement).GetXamlAttribute("Key") : null;
-				if (key == null || key == "") {
-					if (val is Style)
-						key = ((Style)val).TargetType;
-					else if (val is DataTemplate)
-						key = ((DataTemplate)val).DataType;					
-				}
+				//if (key == null || key == "") {
+				//	if (val is Style)
+				//		key = ((Style)val).TargetType;
+				//}
 				if (key == null || key == "")
 					key = val;
 				((ResourceDictionary)collectionInstance).Add(key, val);