  * @default ''
         */
        selectedProperty: '',

        /**
         * Specifies the attribute to set on the selected element to indicate
         * its active state.
         *
         * @attribute selectedAttribute
         * @type string
         * @default 'active'
         */
        selectedAttribute: 'active',

        /**
         * Returns the currently selected element. In multi-selection this returns
         * an array of selected elements.
         * Note that you should not use thi