docs: public void showPreview(int buttonLeft) {
  
          UrlBuilder location = Window.Location.createUrlBuilder();
          location.setParameter(CmsGwtConstants.PARAM_DISABLE_DIRECT_EDIT, Boolean.toString(true));
          location.setParameter(CmsGwtConstants.PARAM_BUTTON_LEFT, Integer.toString(buttonLeft));
          Window.Location.assign(location.buildString());
      }