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;
}
