
        value: null
      },

      /**
       * Gets or sets the selected element. The default is to use the index of the item.
       * @type {string|number}
       */
      selected: {
        type: String,
        notify: true
      },

      /**
       * Returns the currently selected item.
       *
       * @type {?Object}
       */
      selectedItem: {
        type: Object,
        readOnly: true,
        notify: true
      },

      /**
       * The event that fires from items when they are select