code: public static void rebind(Element e) {
      EventsListener ret = getGQueryEventListener(e);
      if (ret != null) {
        DOM.setEventListener((com.google.gwt.user.client.Element) e, ret);
      }
    }
docs: We have to set the gQuery event listener to the element again when
  the element is a widget, because when GWT detaches a widget it removes the
  event listener.