diff --git a/core/lib/Drupal/Core/Menu/LocalActionManager.php b/core/lib/Drupal/Core/Menu/LocalActionManager.php
index e5fbf3b..a6c78b0 100644
--- a/core/lib/Drupal/Core/Menu/LocalActionManager.php
+++ b/core/lib/Drupal/Core/Menu/LocalActionManager.php
@@ -42,7 +42,7 @@ class LocalActionManager extends DefaultPluginManager {
     // The static title for the local action.
     'title' => '',
     // The weight of the local action.
-    'weight' => 0,
+    'weight' => NULL,
     // (Required) the route name used to generate a link.
     'route_name' => NULL,
     // Default route parameters for generating links.