diff -u b/core/modules/action/src/ActionFormBase.php b/core/modules/action/src/ActionFormBase.php
--- b/core/modules/action/src/ActionFormBase.php
+++ b/core/modules/action/src/ActionFormBase.php
@@ -7,14 +7,14 @@
 
 namespace Drupal\action;
 
-use Drupal\Core\Entity\EntityForm;
+use Drupal\Core\Entity\ConfigEntityForm;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\PluginFormInterface;
 
 /**
  * Provides a base form for action forms.
  */
-abstract class ActionFormBase extends EntityForm {
+abstract class ActionFormBase extends ConfigEntityForm {
 
   /**
    * The action plugin being configured.
reverted:
--- b/core/modules/shortcut/src/Form/SwitchShortcutSet.php
+++ a/core/modules/shortcut/src/Form/SwitchShortcutSet.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\shortcut\Form;
 
+use Drupal\Core\Form\FormBase;
-use Drupal\Core\Entity\ConfigEntityForm;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\shortcut\Entity\ShortcutSet;
 use Drupal\shortcut\ShortcutSetStorageInterface;
@@ -17,7 +17,7 @@
 /**
  * Builds the shortcut set switch form.
  */
+class SwitchShortcutSet extends FormBase {
-class SwitchShortcutSet extends ConfigEntityForm {
 
   /**
    * The account the shortcut set is for.
@@ -106,7 +106,7 @@
       $form['id'] = array(
         '#type' => 'machine_name',
         '#machine_name' => array(
+          'exists' => array($this, 'exists'),
-          'exists' => [static::class, 'exists'],
           'replace_pattern' => '[^a-z0-9-]+',
           'replace' => '-',
         ),
@@ -142,6 +142,21 @@
   }
 
   /**
+   * Determines if a shortcut set exists already.
+   *
+   * @param string $id
+   *   The set ID to check.
+   *
+   * @return bool
+   *   TRUE if the shortcut set exists, FALSE otherwise.
+   */
+  public function exists($id) {
+    return (bool) $this->shortcutSetStorage->getQuery()
+      ->condition('id', $id)
+      ->execute();
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function validateForm(array &$form, FormStateInterface $form_state) {