 selection state.

@event core-select
@param {Object} detail
  @param {boolean} detail.isSelected true for selection and false for deselection
  @param {Object} detail.item the item element
-->
<!--
Fired when an item element is tapped.

@event core-activate
@param {Object} detail
  @param {Object} detail.item the item element
-->
<link href="../polymer/polymer.html" rel="import">
<link href="../core-dropdown/core-dropdown.html" rel="import">
<link href="../core-icon-button/core-icon-button.html" rel="impor