Set enabled_langcodes in I18nFormFields in ProviderForm instances

src/pretix/control/forms/event.py

@@ -226,6 +226,8 @@ class ProviderForm(SettingsForm):
             v._required = v.required
             v.required = False
             v.widget.is_required = False
+            if isinstance(v, I18nFormField):
+                v.widget.enabled_langcodes = self.obj.settings.get('locales')
 
     def clean(self):
         cleaned_data = super().clean()

src/pretix/plugins/banktransfer/payment.py

@@ -19,7 +19,6 @@ class BankTransfer(BasePaymentProvider):
             label=_('Bank account details'),
             widget=I18nTextarea,
         )
-        form_field.widget.enabled_langcodes = self.event.settings.get('locales')
         return OrderedDict(
             list(super().settings_form_fields.items()) + [('bank_details', form_field)]
         )