return true;
	public boolean undo()	{		if(undo == null)			return false;		try		{			setFlag(UNDO_IN_PROGRESS,true);			undo.undo();			return true;		}		catch(CannotUndoException cu)		{			Log.log(Log.DEBUG,this,cu);			return false;		}		finally		{			setFlag(UNDO_IN_PROGRESS,false);		}	}