code: public function handle(GetOperationButtonEvent $event)
      {
          if (!$this->wantToHandle($event)) {
              return;
          }
  
          $command = $event->getCommand();
          if ($command->getName() == 'dca_combine') {
              $event->setHref(
                  UrlBuilder::fromUrl($event->getHref())
                      ->setQueryParameter(
                          'id',
                          ModelId::fromValues('tl_metamodel_dca_combine', $event->getModel()->getId())->getSerialized()
                      )
                      ->getUrl()
              );
          }
      }
docs: Clear the button if the User is not admin.
  
  @param GetOperationButtonEvent $event The event.
  
  @return void