diff --git a/core/lib/Drupal/Core/Render/Element/Page.php b/core/lib/Drupal/Core/Render/Element/Page.php
index 4156ab4..f12c8f3 100644
--- a/core/lib/Drupal/Core/Render/Element/Page.php
+++ b/core/lib/Drupal/Core/Render/Element/Page.php
@@ -12,7 +12,7 @@
  *
  * @RenderElement("page")
  */
-class Page {
+class Page extends RenderElement {
 
   /**
    * {@inheritdoc}