docs: function () {
              if (this._$source) {
                  var item, items = [];
                  for (var i = 0; i < this.$items.length; i++) {
                      item = this.$items[i];
                      if (item instanceof Bindable && item.sync()) {
                          item = item._$source;
                      }
                      items.push(item);
                  }
                  this._$source.reset(items);
              }
              return this.callBase();
          }