Preserve user's chosen locale in Editor

src/Event/Subscriber/LocaleSubscriber.php

@@ -4,15 +4,25 @@ declare(strict_types=1);
 
 namespace Bolt\Event\Subscriber;
 
+use Bolt\Entity\User;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\RequestEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
 
 class LocaleSubscriber implements EventSubscriberInterface
 {
+    /** @var string s */
+    private $defaultLocale;
+
+    public function __construct(string $defaultLocale)
+    {
+        $this->defaultLocale = $defaultLocale;
+    }
+
     public function onKernelRequest(RequestEvent $event): void
     {
         $request = $event->getRequest();
+
         if (! $request->hasPreviousSession()) {
             return;
         }
@@ -25,6 +35,15 @@ class LocaleSubscriber implements EventSubscriberInterface
             $locale = $request->query->get('_locale');
             $request->getSession()->set('_locale', $locale);
             $request->setLocale($locale);
+        } elseif ($request->attributes->get('zone', false) === 'backend') {
+            /** @var User|null $user */
+            $user = $request->getUser();
+            if ($user && $user->getLocale()) {
+                $locale = $user->getLocale();
+            } else {
+                $locale = $this->defaultLocale;
+            }
+            $request->setLocale($locale);
         } elseif ($request->getSession()->has('_locale')) {
             // if no explicit locale has been set on this request, use one from the session
             $request->setLocale($request->getSession()->get('_locale'));