internal override void Update(Change change) { var _change = change as ListPropertyChange; var newAddList = new List<object>(AddedItems.Except(_change.RemovedItems).Concat(_change.AddedItems.Except(RemovedItems).Except(AddedItems))); var newRemoveList = new List<object>(RemovedItems.Except(_change.AddedItems).Concat(_change.RemovedItems.Except(AddedItems).Except(RemovedItems))); AddedItems = newAddList; RemovedItems = newRemoveList; }