code: function tabView_open() {
      var menuitem = new elementslib.Elem(this._controller.menus['view-menu'].menu_tabview);
      this._controller.click(menuitem);
      this.waitForOpened();
  
      this._tabView = this.getElement({type: "tabView"});
      this._tabViewDoc = this._tabView.getNode().webNavigation.document;
    }
docs: Open the Tab View