docs: function tabView_waitForClosed() {
      // Add event listener to wait until the tabview has been closed
      var self = { closed: false };
      function checkClosed() { self.closed = true; }
      this._controller.window.addEventListener("tabviewhidden", checkClosed, false);
  
      try {
        mozmill.utils.waitFor(function() {
          return self.closed == true;
        }, TIMEOUT, 100, "TabView is still open.");
      } finally {
        this._controller.window.removeEventListener("tabviewhidden", checkClosed, false);
      }
  
      this._tabViewObject = null;
      this._groupItemsObject = null;
      this._tabItemsObject = null;
    }