code: private void setBusy(boolean busy) {
  
          if (busy) {
              getElement().addClassName(I_CmsLayoutBundle.INSTANCE.notificationCss().busy());
          } else {
              getElement().removeClassName(I_CmsLayoutBundle.INSTANCE.notificationCss().busy());
          }
      }
docs: Toggles the busy icon.<p>
  
  @param busy <code>true</code> to show the busy icon