code: function _handlePaneMerge(e, paneId) {
          var index;
          var targetPaneId = MainViewManager.FIRST_PANE;
  
          $.each(_mrofList, function (itrIndex, value) {
              if (value && value.paneId === paneId) { // We have got an entry which needs merge
                  // Before modifying the actual pane info check if an entry exists with same target pane
                  index = _.findIndex(_mrofList, function (record) {
                      return (record && record.file === value.file && record.paneId === targetPaneId);
                  });
                  if (index !== -1) { // A duplicate entry found, remove the current one instead of updating
                      _mrofList[index] = null;
                  } else { // Update with merged pane info
                      _mrofList[itrIndex].paneId = targetPaneId;
                  }
              }
          });
  
          // Clean the null/undefined entries
          _mrofList = _mrofList.filter(function (e) {return e; });
  
          PreferencesManager.setViewState(OPEN_FILES_VIEW_STATE, _mrofList, _getPrefsContext(), true);
      }
docs: Merges the entries to a single pane if split view have been merged Then purges duplicate entries in mrof list