Popup')          .on('click', zoom);        popup.each(drawTransition);        state.onStateChanged(function () {          that.update(000)      });        d0.select(window).on('click', function () {          if (zoomedLink !== null) {              zoom(zoomedLink);          } else if (selectedLink !== null) {              updateSelection(selectedLink);          }      });        return that;  }    