code: public function handle(ManipulateWidgetEvent $event)
      {
          if (!($this->wantToHandle($event) && ('tl_class' === $event->getProperty()->getName()))) {
              return;
          }
  
          $link = ' <a href="%1$s" onclick="Backend.getScrollOffset();Backend.openModalIframe({' .
              '\'width\':765,' .
              '\'title\':\'%2$s\',' .
              '\'url\':this.href,' .
              '\'id\':\'%3$s\'' .
              '});return false">%4$s</a>';
  
          $image = $this->iconBuilder->getBackendIconImageTag(
              'bundles/metamodelscore/images/icons/dca_wizard.png',
              $event->getEnvironment()->getTranslator()->translate('stylepicker', 'tl_metamodel_dca'),
              'style="vertical-align:top;"'
          );
  
          $event->getWidget()->wizard = sprintf(
              $link,
              $this->urlGenerator->generate('metamodels.picker', [
                  'tbl' => $event->getEnvironment()->getDataDefinition()->getName(),
                  'fld' => $event->getProperty()->getName(),
                  'inputName' => 'ctrl_' . $event->getProperty()->getName(),
                  'id' => $event->getModel()->getId(),
                  'item' => 'PALETTE_STYLE_PICKER',
              ]),
              addslashes($event->getEnvironment()->getTranslator()->translate('stylepicker', 'tl_metamodel_dca')),
              $event->getModel()->getId(),
              $image
          );
      }
docs: Calculate the wizard.
  
  @param ManipulateWidgetEvent $event The event.
  
  @return void