public function onBeforeRender(FileAttachmentField $field)
 {
     if ($field->getSetting('sortable') && $this->owner->isCMS()) {
         $field->setSetting('sortable-action', $field->Link('sort'));
         $field->setSetting('sort-column', $this->getSortableColumn());
         $field->addExtraClass('is-sortable');
         Requirements::javascript(DROPZONE_SORTABLE_DIR . '/javascript/dropzone-sortable.js');
         Requirements::css(DROPZONE_SORTABLE_DIR . '/css/dropzone-sortable.css');
     }
 }
 public function Link($action = null)
 {
     if ($this->multiRecordAction) {
         return $this->form->FormAction() . '/field/' . $this->multiRecordAction . '/' . $action;
     }
     return parent::Link($action);
 }