/**
  * This will add the fallback value (val field after save) to the display fields component,
  * so it can be saved by @GridFieldEditableColumns
  *
  * @param GridField            $grid
  * @param GridFieldDataColumns $editable
  */
 private function addFallbackValueToDisplayFields(GridField $grid, GridFieldDataColumns $editable)
 {
     $fields = $editable->getDisplayFields($grid);
     if (!isset($fields[$this->valFieldAfterSave])) {
         $editable->setDisplayFields($fields + [$this->valFieldAfterSave => $this->valFieldAfterSave]);
     }
 }