diff -u b/core/modules/block/src/Controller/BlockLibraryController.php b/core/modules/block/src/Controller/BlockLibraryController.php
--- b/core/modules/block/src/Controller/BlockLibraryController.php
+++ b/core/modules/block/src/Controller/BlockLibraryController.php
@@ -104,8 +104,8 @@
     $region = $request->query->get('region');
     $weight = $request->query->get('weight');
 
-    // Adds to the "Add custom block" action url route parameters, to provide
-    // correct region setting after creation.
+    // Add url route parameters to provide correct region setting
+    // after creation.
     $add_action_url = $build['local_actions']['block_content_add_action']['#link']['url'] ?? NULL;
     if ($add_action_url instanceof Url) {
       $add_action_url->setRouteParameter('region', $region);
diff -u b/core/modules/block_content/src/Plugin/Menu/LocalAction/BlockContentAddLocalAction.php b/core/modules/block_content/src/Plugin/Menu/LocalAction/BlockContentAddLocalAction.php
--- b/core/modules/block_content/src/Plugin/Menu/LocalAction/BlockContentAddLocalAction.php
+++ b/core/modules/block_content/src/Plugin/Menu/LocalAction/BlockContentAddLocalAction.php
@@ -22,7 +22,7 @@
     }
 
     // If the current request has a region query parameter.
-    if ($region = \Drupal::request()->query->get('region')) {
+    if ($region = $this->request->query->get('region')) {
       $options['query']['region'] = $region;
     }
 
diff -u b/core/modules/block_content/tests/src/Functional/BlockContentListTest.php b/core/modules/block_content/tests/src/Functional/BlockContentListTest.php
--- b/core/modules/block_content/tests/src/Functional/BlockContentListTest.php
+++ b/core/modules/block_content/tests/src/Functional/BlockContentListTest.php
@@ -71,4 +71,23 @@
 
   /**
+   * Tests that region value is retained when we create new block.
+   */
+  public function testBlockRegionPlacement() {
+    $this->drupalLogin($this->drupalCreateUser([
+      'administer blocks',
+      'translate configuration',
+    ]));
+    $this->drupalGet("admin/structure/block/library/stark", ['query' => ['region' => 'help']]);
+
+    $this->clickLink('Add custom block');
+    $this->assertSession()->statusCodeEquals(200);
+    $edit = [
+      'info[0][value]' => $this->randomString(),
+    ];
+    $this->submitForm($edit, 'Save');
+    $this->assertSession()->fieldValueEquals('region', 'help');
+  }
+
+  /**
    * Tests the custom block listing page with different permissions.
    */
@@ -120,23 +139,4 @@
     $this->assertSession()->pageTextNotContains('Non-reusable block');
-  }
-
-  /**
-   * Tests that region value is retained when we create new block.
-   */
-  public function testBlockRegionPlacement() {
-    $this->drupalLogin($this->drupalCreateUser([
-      'administer blocks',
-      'translate configuration',
-    ]));
-    $this->drupalGet("admin/structure/block/library/stark", ['query' => ['region' => 'help']]);
-
-    $this->clickLink('Add custom block');
-    $this->assertSession()->statusCodeEquals(200);
-    $edit = [
-      'info[0][value]' => $this->randomString(),
-    ];
-    $this->submitForm($edit, 'Save');
-    $this->assertSession()->fieldValueEquals('region', 'help');
   }
 
 }
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Menu/LocalActionDefault.php
+++ b/core/lib/Drupal/Core/Menu/LocalActionDefault.php
@@ -26,6 +26,13 @@ class LocalActionDefault extends PluginBase implements LocalActionInterface, Con
    */
   protected $routeProvider;
 
+  /**
+   * The current request.
+   *
+   * @var \Symfony\Component\HttpFoundation\Request
+   */
+  protected $request;
+
   /**
    * Constructs a LocalActionDefault object.
    *
@@ -37,11 +44,14 @@ class LocalActionDefault extends PluginBase implements LocalActionInterface, Con
    *   The plugin implementation definition.
    * @param \Drupal\Core\Routing\RouteProviderInterface $route_provider
    *   The route provider to load routes by name.
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The current request.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, RouteProviderInterface $route_provider) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, RouteProviderInterface $route_provider, Request $request) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
 
     $this->routeProvider = $route_provider;
+    $this->request = $request;
   }
 
   /**
@@ -52,7 +62,8 @@ public static function create(ContainerInterface $container, array $configuratio
       $configuration,
       $plugin_id,
       $plugin_definition,
-      $container->get('router.route_provider')
+      $container->get('router.route_provider'),
+      $container->get('request_stack')->getCurrentRequest(),
     );
   }