docs: public void catchNotifications() {
  
          m_catchNotifications = true;
          if (isShowing()) {
              installNotificationWidget();
          }
          if (m_closingHandlerRegistration == null) {
              // when closing the dialog
              m_closingHandlerRegistration = addCloseHandler(new CloseHandler<PopupPanel>() {
  
                  /**
                   * @see CloseHandler#onClose(CloseEvent)
                   */
                  public void onClose(CloseEvent<PopupPanel> event) {
  
                      clearNotifications();
                  }
              });
          }
      }