diff --git a/core/modules/node/src/Entity/NodeType.php b/core/modules/node/src/Entity/NodeType.php
index 91d8a90..923f9e5 100644
--- a/core/modules/node/src/Entity/NodeType.php
+++ b/core/modules/node/src/Entity/NodeType.php
@@ -90,7 +90,7 @@ class NodeType extends ConfigEntityBundleBase implements NodeTypeInterface {
    *
    * @var int
    */
-  protected $preview_mode = DRUPAL_OPTIONAL;
+  protected $preview_mode = 1;
 
   /**
    * Display setting for author and date Submitted by post information.