docs: function (event) {
              // flag that avoids to trigger the user callback when browsing the checkbox list
              var avoidCallback = (this._hasFocus || this._keepFocus);
              this.$TextInput._dom_onfocus.call(this, event, true);
              if (this._cfg.onfocus && !avoidCallback) {
                  this.evalCallback(this._cfg.onfocus);
              }
          }