question: public void addLongSelectionListener ( SelectionListener listener ) { if ( listener == null ) throw new IllegalArgumentException ( ) ; if ( hexEditControl == null ) { if ( listOfLongListeners == null ) listOfLongListeners = new ArrayList < > ( ) ; listOfLongListeners . add ( listener ) ; } else { hexEditControl . addLongSelectionListener ( listener ) ; } }
target:  Adds a long selection listener. Events sent to the listener have long start and end points.