Preserve user's chosen locale in Editor

src/Controller/Backend/UserEditController.php

@@ -195,6 +195,9 @@ public function save(?User $user, ValidatorInterface $validator): Response
         $this->em->persist($user);
         $this->em->flush();
 
+        $event = new UserEvent($user);
+        $this->dispatcher->dispatch($event, UserEvent::ON_POST_SAVE);
+
         $this->addFlash('success', 'user.updated_profile');
 
         return $this->redirectToRoute('bolt_users');

src/Event/Subscriber/LocaleSubscriber.php

@@ -13,6 +13,7 @@ class LocaleSubscriber implements EventSubscriberInterface
     public function onKernelRequest(RequestEvent $event): void
     {
         $request = $event->getRequest();
+
         if (! $request->hasPreviousSession()) {
             return;
         }
@@ -25,7 +26,10 @@ public function onKernelRequest(RequestEvent $event): void
             $locale = $request->query->get('_locale');
             $request->getSession()->set('_locale', $locale);
             $request->setLocale($locale);
+        } elseif ($request->attributes->get('zone', false) === 'backend' && $request->getSession()->has('_backend_locale')) {
+            $request->setLocale($request->getSession()->get('_backend_locale'));
         } elseif ($request->getSession()->has('_locale')) {
+            // @todo: This is probably never reached. Remove if you're brave enough ;-)
             // if no explicit locale has been set on this request, use one from the session
             $request->setLocale($request->getSession()->get('_locale'));
         }

src/Event/Subscriber/UserLocaleSubscriber.php

@@ -5,6 +5,7 @@
 namespace Bolt\Event\Subscriber;
 
 use Bolt\Entity\User;
+use Bolt\Event\UserEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\Session\SessionInterface;
 use Symfony\Component\Security\Http\Event\InteractiveLoginEvent;
@@ -18,19 +19,30 @@ class UserLocaleSubscriber implements EventSubscriberInterface
 {
     private $session;
 
-    public function __construct(SessionInterface $session)
+    /** @var string */
+    private $defaultLocale;
+
+    public function __construct(SessionInterface $session, string $defaultLocale)
     {
         $this->session = $session;
+        $this->defaultLocale = $defaultLocale;
     }
 
     public function onInteractiveLogin(InteractiveLoginEvent $event): void
     {
         /** @var User $user */
         $user = $event->getAuthenticationToken()->getUser();
+        $this->updateBackendLocale($user);
+    }
+
+    public function onUserEdit(UserEvent $event): void
+    {
+        $this->updateBackendLocale($event->getUser());
+    }
 
-        if ($user->getLocale() !== null) {
-            $this->session->set('_locale', $user->getLocale());
-        }
+    private function updateBackendLocale(User $user): void
+    {
+        $this->session->set('_backend_locale', $user->getLocale() ?? $this->defaultLocale);
     }
 
     public static function getSubscribedEvents()

src/Event/UserEvent.php

@@ -10,6 +10,7 @@
 class UserEvent
 {
     public const ON_EDIT = 'bolt.users_pre_edit';
+    public const ON_POST_SAVE = 'bolt.users_post_save';
 
     /** @var User */
     private $user;
@@ -28,11 +29,19 @@ public function __construct(User $user, ?Collection $roleOptions = null)
         }
     }
 
+    /**
+     * @deprecated
+     */
     public function getContent(): User
     {
         return $this->user;
     }
 
+    public function getUser(): User
+    {
+        return $this->user;
+    }
+
     public function getRoleOptions(): Collection
     {
         return $this->rolesOptions;