ateSelected();
      }
      this._addListener(this.activateEvent);
    },

    detached: function() {
      if (this._observer) {
        Polymer.dom(this).unobserveNodes(this._observer);
      }
      this._removeListener(this.activateEvent);
    },

    /**
     * Returns the index of the given item.
     *
     * @method indexOf
     * @param {Object} item
     * @returns Returns the index of the item
     */
    indexOf: function(item) {
      return this.items.indexOf(item);
    },

    /**
     * Sel