void gridPropertyValueChanged(object s, PropertyValueChangedEventArgs e)
        {
            _memento.EndCommand( );

            _memento.BeginCommand(@"Edit '{0}' property".FormatWith(getNameOfChangedItem(e.ChangedItem)));

            _currentItem.PropertiesChanged(e);

            var itemEditor = _currentItem as ItemEditor;

            if (itemEditor != null)
            {
                //debt: Should we not notify the model about other non 'ItemEditor' changes, such as the level itself and the layers?
                IoC.Model.NotifyChanged(itemEditor);
            }
        }
 void entityTreeDragDrop(object sender, DragEventArgs e)
 {
     _memento.EndCommand( );
 }