code: function _sortWorkingSet(paneId, compareFn) {
          _forEachPaneOrPanes(paneId, function (pane) {
              pane.sortViewList(compareFn);
              exports.trigger("workingSetSort", pane.id);
          });
      }
docs: sorts the pane's view list
  @param {!string} paneId - id of the pane to sort, ALL_PANES or ACTIVE_PANE
  @param {sortFunctionCallback} compareFn - callback to determine sort order (called on each item)
  @see {@link Pane#sortViewList} for more information
  @see {@link https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/sort|Sort Array - MDN}
  @private