code: function() {
      var tracker = this._aSelections;
      if(tracker && tracker.length > 0) {
          for(var i=tracker.length-1; i>-1; i--) {
             if(lang.isString(tracker[i])){
                  return tracker[i];
              }
          }
      }
  }
docs: Returns last selected Record ID.
  
  @method getLastSelectedRecord
  @return {String} Record ID of last selected row.