   }
          }
        }

        return false;
      },

      _scrollInteractionHandler: function(event) {
        var scrolledElement =
            /** @type {HTMLElement} */(Polymer.dom(event).rootTarget);
        if (Polymer
              .IronDropdownScrollManager
              .elementIsScrollLocked(scrolledElement)) {
          if (event.type === 'keydown' &&
              !Polymer.IronDropdownScrollManager._isScrollingKeypress(event)) {
            return;
          }

          event.preventDefa