client/public/elements/components/dropdown.js
/**
   * @method _onDropdownArrow
   * @description Bound to arrow down/up events on iron-dropdown
   * @param {CustomEvent} e - Inherited from IronA11yKeysBehavior
   */
@method _onDropdownArrow
@description Bound to arrow down/up events on iron-dropdown
@param {CustomEvent} e - Inherited from IronA11yKeysBehavior
@method _onDropdownArrow @description Bound to arrow down / up events on iron - dropdown @param { CustomEvent } e - Inherited from IronA11yKeysBehavior
_onDropdownArrow(e) {
    e.preventDefault();
    let target = this.shadowRoot.activeElement;
    let ke = e.detail.keyboardEvent;
    if (target && ke) {
      if (ke.code == 'ArrowUp' && target.previousElementSibling) {
        target.previousElementSibling.focus();
      } else if(ke.code == 'ArrowDown' && target.nextElementSibling) {
        target.nextElementSibling.focus();
      }
    }
  }
_onDropdownArrow ( e ) { e . preventDefault ( ) ; let target = this . shadowRoot . activeElement ; let ke = e . detail . keyboardEvent ; if ( target && ke ) { if ( ke . code == 'ArrowUp' && target . previousElementSibling ) { target . previousElementSibling . focus ( ) ; } else if ( ke . code == 'ArrowDown' && target . nextElementSibling ) { target . nextElementSibling . focus ( ) ; } } }
@method _onDropdownArrow
 @description Bound to arrow down/up events on iron-dropdown
 @param {CustomEvent} e - Inherited from IronA11yKeysBehavior
@method _onDropdownArrow @description Bound to arrow down / up events on iron - dropdown @param { CustomEvent } e - Inherited from IronA11yKeysBehavior