docs: function (newValue) {
  
              var data = this._data;
              if (newValue == null) {
                  // a null value is allowed for the selectedIndex property, but it cannot be used to set the property
                  // as it means several items are selected and we do not know which ones
                  // just ignore the null value
                  return;
              }
              var items = data.items;
  
              if (newValue < 0) {
                  return false;
              } else if (newValue >= items.length) {
                  return false;
              } else {
  
                  this.json.setValue(data, "focusIndex", newValue);
                  this.setFocus(data.focusIndex);
                  return true;
  
              }
          }