question: protected WSDisplay createDisplay ( Frame owner ) { WSDisplay wsd ; if ( persistentDisplayType == null && Environment . getBoolean ( Environment . UseInternalFrames ) ) { wsd = new IntrnlFrm ( title ) ; } else { Class wTypeClass = persistentDisplayType == null ? getDefaultWindowSupportDisplayType ( ) : persistentDisplayType ; if ( wTypeClass == Dlg . class ) { wsd = new Dlg ( owner , title ) ; } else if ( wTypeClass == IntrnlFrm . class ) { wsd = new IntrnlFrm ( title ) ; } else { wsd = new Frm ( title ) ; } } setFavIcon ( wsd ) ; setDisplay ( wsd ) ; return wsd ; }
target:  Called when a component hasn't specified what kind of window they want. If the Environment.useInternalFrames flag isn't set, then the getDefaultWindowSupportDisplayType() method is called to find out which WSDisplay type class should be created for the component. IF that returns null, a Frm is created.