diff --git a/core/modules/book/src/Form/BookSettingsForm.php b/core/modules/book/src/Form/BookSettingsForm.php
index 29590ccdb5..2d50c867c8 100644
--- a/core/modules/book/src/Form/BookSettingsForm.php
+++ b/core/modules/book/src/Form/BookSettingsForm.php
@@ -45,7 +45,6 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#options' => $types,
       '#required' => TRUE,
     ];
-    $form['array_filter'] = ['#type' => 'value', '#value' => TRUE];
 
     return parent::buildForm($form, $form_state);
   }