@Override
 public void dispose() {
   fFilterActionGroup.dispose();
   fShowActionGroup.dispose();
   fChangeListener = null;
   ISelectionProvider selectionProvider = fSite.getSelectionProvider();
   selectionProvider.removeSelectionChangedListener(fWorkingSetAssignementAction);
   super.dispose();
 }
 public void setWorkingSetModel(WorkingSetModel model) {
   fShowActionGroup.setWorkingSetMode(model);
   fWorkingSetAssignementAction.setWorkingSetModel(model);
 }