set except set elem model collabor factori creat collabor model uml collabor repres oper combo box model target manag instanc set target elem thread helper synchron project project manag manag current project object root object clazz model core factori build oper model core factori creat oper model core helper set owner oper clazz model collabor helper set repres oper elem oper thread helper synchron simul target chang model target set target event object elem thread helper synchron 