docs: function (filteredIn) {
                  if (filteredIn == null) {
                      filteredIn = true;
                  }
                  // if not already done, we must first refresh the initial array before marking all elements:
                  this._refreshInitialArray();
                  var items = this.items;
                  var itemsLength = items.length;
                  for (var i = 0; i < itemsLength; i++) {
                      json.setValue(items[i], "filteredIn", filteredIn, this._jsonChangeCallback);
                  }
                  this.notifyChange(this._CHANGED_FILTERED_IN);
              }