public Pause(Lookup lookup) {
    Icon icon = ImageUtilities.image2Icon(ImageUtilities.loadImage("resources/16x16-pause.png"));
    putValue(SMALL_ICON, icon);

    this.setEnabled(true);

    backend = CentralLookup.getDefault().lookup(BackendAPI.class);
    backend.addUGSEventListener(this);
  }
 @Override
 public boolean isEnabled() {
   return backend.canPause();
 }