code: function() {
          var columnRange = this.selectionModel.get('range').column;
          var visibleColumns = this.columnModel.getVisibleColumns();
          var selectedColumns = visibleColumns.slice(columnRange[0], columnRange[1] + 1);
  
          return _.pluck(selectedColumns, 'name');
      }
docs: Returns an array of names of columns in selection range.
  @private
  @returns {Array.<String>}