docs: function (lastTypedKeys, newMatch) {
                  var LABEL_META = this.LABEL_META;
                  var options = this._dataModel.listContent;
                  var keyNbr = lastTypedKeys.length;
                  var index = this._dataModel.selectedIdx + (newMatch ? 1 : 0); // start point to search for a match
                  for (var ct = 0, optionsLength = options.length; ct < optionsLength; ct++, index++) {
                      if (index >= optionsLength) {
                          index = 0;
                      }
                      var opt = options[index];
                      var prefix = opt[LABEL_META].substr(0, keyNbr);
                      if (prefix == lastTypedKeys) {
                          return index;
                      }
                  }
                  return -1; // not found
              }