super.init( action, def );
final MasterDetailsContentNodePart node = (MasterDetailsContentNodePart) getPart();
final MasterDetailsEditorPagePart page = node.nearest( MasterDetailsEditorPagePart.class );
this.service = page.service( ProblemsTraversalService.class );
final Listener listener = new Listener()
{
@Override
public void handle( final Event event )