code: function cacheScrollState(paneId) {
          _forEachPaneOrPanes(paneId, function (pane) {
              _paneScrollStates[pane.id] = pane.getScrollState();
          });
      }
docs: Caches the specified pane's current scroll state
  If there was already cached state for the specified pane, it is discarded and overwritten
  @param {!string} paneId - id of the pane in which to cache the scroll state,
  ALL_PANES or ACTIVE_PANE