code: function findInAllWorkingSets(fullPath) {
          var index,
              result = [];
  
          _.forEach(_panes, function (pane) {
              index = pane.findInViewList(fullPath);
              if (index >= 0) {
                  result.push({paneId: pane.id, index: index});
              }
          });
  
          return result;
      }
docs: Finds all instances of the specified file in all working sets.
  If there is a temporary view of the file, it is not part of the result set
  @param {!string} fullPath - path of the file to find views of
  @return {Array.<{pane:string, index:number}>} an array of paneId/index records