 (this.children.length !== 1) return null;
        var child = this.firstElementChild;
        if ('selected' in child && 'items' in child) {  // Quack!
          return child;
        }
      },

      _observeManagedSelector: function() {
        if (!this._managedSelector) return;

        this._observer = new PathObserver(this._managedSelector, 'selectedIndex');
        this._observer.open(function(newIndex) {
          if (this.selectedIndex === this._managedSelector.selectedIndex) return;
          va