        if (this.disabled) {
            return;
          }

          this.$.dropdown.open();
        },

        /**
         * Hide the dropdown content.
         */
        close: function() {
          this.$.dropdown.close();
        },

        /**
         * When an `iron-select` event is received, the dropdown should
         * automatically close on the assumption that a value has been chosen.
         *
         * @param {CustomEvent} event A CustomEvent instance with type
         * set to `"ir