private Button createDeleteButton() {
    Button button =
        new Button(
            "",
            new SelectionListener<ButtonEvent>() {

              @Override
              public void componentSelected(ButtonEvent ce) {
                FeatureInjector injector = FeatureInjector.MainInjector.getInstance();
                GPEventBus bus = injector.getEventBus();
                bus.fireEvent(
                    new DeleteAttributeConditionEvent(FeatureAttributeConditionField.this));
              }
            });
    button.setToolTip("Delete Condition");
    button.setIcon(BasicWidgetResources.ICONS.delete());
    button.setAutoWidth(true);

    return button;
  }