diff --git a/src/Form/Extension/OrderTypeExtension.php b/src/Form/Extension/OrderTypeExtension.php
index ecd22af..a38c9a5 100644
--- a/src/Form/Extension/OrderTypeExtension.php
+++ b/src/Form/Extension/OrderTypeExtension.php
@@ -24,7 +24,7 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
 
             $form
                 ->add('items', OrderItemCollectionType::class, [
-                    'entry_options' => ['currency_code' => $order->getCurrencyCode()]
+                    'entry_options' => ['currency_code' => $order->getCurrencyCode()],
                 ])
             ;
 
diff --git a/src/Form/Type/OrderItemType.php b/src/Form/Type/OrderItemType.php
index 11b0d72..6b09406 100644
--- a/src/Form/Type/OrderItemType.php
+++ b/src/Form/Type/OrderItemType.php
@@ -5,7 +5,6 @@
 namespace Setono\SyliusOrderEditPlugin\Form\Type;
 
 use Sylius\Bundle\ResourceBundle\Form\Type\AbstractResourceType;
-use Sylius\Component\Core\Model\OrderInterface;
 use Sylius\Component\Core\Model\OrderItemInterface;
 use Sylius\Component\Core\Model\ProductVariant;
 use Sylius\Component\Order\Modifier\OrderItemQuantityModifierInterface;
@@ -14,8 +13,6 @@
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\Form\FormEvent;
 use Symfony\Component\Form\FormEvents;
-use Symfony\Component\Form\FormInterface;
-use Symfony\Component\Form\FormView;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 final class OrderItemType extends AbstractResourceType
@@ -47,6 +44,7 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
             ])
         ;
 
+        /** @var string $currencyCode */
         $currencyCode = $options['currency_code'];
 
         $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) use ($currencyCode): void {
@@ -75,5 +73,6 @@ public function configureOptions(OptionsResolver $resolver): void
         parent::configureOptions($resolver);
 
         $resolver->setRequired('currency_code');
+        $resolver->setAllowedTypes('currency_code', 'string');
     }
 }