date: function() {
      return this.inputElement.validate();
    },

    /**
     * Forward focus to inputElement
     */
    _onFocus: function() {
      if (!this._shiftTabPressed) {
        this._focusableElement.focus();
      }
    },

    /**
     * Handler that is called when a shift+tab keypress is detected by the menu.
     *
     * @param {CustomEvent} event A key combination event.
     */
    _onShiftTabDown: function(event) {
      var oldTabIndex = this.getAttribute('tabindex');
      this._s