java - Menu accelerator SWT.ALT+SWT.ARROW is not triggered -

i'm using swt 4.4.2 (win32) build graphical user interface simple mp3 player application.
in swt tree show folders , files play.
want change volume of playing file clicking menu item , pressing alt+arrow_up , alt+arrow_down.

so have these components:

tree = new tree(shell, swt.border | swt.full_selection | swt.single | swt.v_scroll); tree.setlinesvisible(true); tree.setlocation(10, 10); tree.setsize(240, 440);  audioloudermenu = new menuitem(audiovolumemenu, swt.push); audioloudermenu.setaccelerator(swt.alt | swt.arrow_up); audioloudermenu.settext("louder"); audioloudermenu.addlistener(swt.selection, audiovolumemenuhandler);  audioquietermenu = new menuitem(audiovolumemenu, swt.push); audioquietermenu.setaccelerator(swt.alt | swt.arrow_down); audioquietermenu.settext("quieter"); audioquietermenu.addlistener(swt.selection, audiovolumemenuhandler); 

the problem if tree view has focus , press alt+arrow_down entry in tree selected , not shortcut of menu item triggered.

is bug of swt , how can solve problem? know can define shortcut think should possible use alt+arrow_up/down...

this isn't bug (platform-dependant) keyboard navigation feature of tree.

i recommend choose different shortcut audio volume in order not confuse users. if nonetheless want use alt+arrow_down, can try prevent tree consuming key combination , give menu chance consume it:

tree.addlistener( swt.keydown, new listener() {   @override   public void handleevent( event event ) {     if( event.keycode == swt.arrow_down && ( event.statemask & swt.mod3 ) != 0 ) {       event.doit = false;     }   } } );