action perform action event action perform object sourc sourc collect old stereo object stereo object target sourc uml combo box uml combo box combo uml combo box sourc model facad stereotyp combo select item stereo combo select item model facad model element combo target target combo target old stereo model facad stereotyp target equal combo select item stereo old stereo old stereo contain stereo target add stereotyp submenu stereo model core helper add stereotyp target stereo 