diff --git a/list_predefined_options.module b/list_predefined_options.module
index e6cae8e421d54e9680ed72dec56efe62fffb8b04..1631924bf08d9edf1bac8a4c9dc6096a9ac1b1cf 100644
--- a/list_predefined_options.module
+++ b/list_predefined_options.module
@@ -11,11 +11,13 @@ use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 
 /**
- * Implements hook_form_FORM_ID_alter(): field_storage_config_edit_form.
+ * Implements hook_form_FORM_ID_alter(): field_config_edit_form.
  */
-function list_predefined_options_form_field_storage_config_edit_form_alter(&$form, FormStateInterface $form_state, $form_id) {
-  /** @var \Drupal\Core\Field\FieldConfigInterface $field */
+function list_predefined_options_form_field_config_edit_form_alter(&$form, FormStateInterface $form_state, $form_id) {
+  /** @var \Drupal\field\Entity\FieldConfig $field */
   $field = $form_state->getFormObject()->getEntity();
+  /** @var \Drupal\field\Entity\FieldStorageConfig $field_storage */
+  $field_storage = $field->getFieldStorageDefinition();
 
   $field_types = [
     'list_float',
@@ -23,12 +25,12 @@ function list_predefined_options_form_field_storage_config_edit_form_alter(&$for
     'list_string',
   ];
 
-  if (in_array($field->getType(), $field_types)) {
-    $options = \Drupal::service('plugin.manager.list_options')->listOptions($field->getType());
+  if (in_array($field_storage->getType(), $field_types)) {
+    $options = \Drupal::service('plugin.manager.list_options')->listOptions($field_storage->getType());
     $options = ['' => t('Custom')] + $options;
 
-    $settings = $field->getThirdPartySettings('list_predefined_options');
-    $form['list_predefined_options_plugin_id'] = [
+    $settings = $field_storage->getThirdPartySettings('list_predefined_options');
+    $form['field_storage']['subform']['list_predefined_options_plugin_id'] = [
       '#type' => 'select',
       '#title' => t('Allowed values'),
       '#options' => $options,
@@ -37,27 +39,27 @@ function list_predefined_options_form_field_storage_config_edit_form_alter(&$for
     ];
 
     // Workaround for https://www.drupal.org/project/drupal/issues/3441061.
-    $form['settings']['allowed_values']['#type'] ??= 'container';
+    $form['field_storage']['subform']['settings']['allowed_values']['#type'] ??= 'container';
 
     // Hide the values textarea when a list options plugin is selected.
-    $form['settings']['allowed_values']['#states']['visible'] = [
+    $form['field_storage']['subform']['settings']['allowed_values']['#states']['visible'] = [
       ':input[name="field_storage[subform][list_predefined_options_plugin_id]"]' => ['value' => ''],
     ];
 
     // Change the allowed values inputs in the table to not be required. It's
     // too complicated to support validation conditionally, and the form states
     // take care of this in the browser.
-    $form['settings']['allowed_values']['table'][0]['item']['key']['#required'] = FALSE;
-    $form['settings']['allowed_values']['table'][0]['item']['label']['#required'] = FALSE;
+    $form['field_storage']['subform']['settings']['allowed_values']['table'][0]['item']['key']['#required'] = FALSE;
+    $form['field_storage']['subform']['settings']['allowed_values']['table'][0]['item']['label']['#required'] = FALSE;
 
     // Set the allowed values inputs in the table to not required using form
     // states when a list options plugin is selected. Only inputs from first
     // table row are required, so it's safe to use [0] here. @see
     // \Drupal\options\Plugin\Field\FieldType\ListItemBase::storageSettingsForm().
-    $form['settings']['allowed_values']['table'][0]['item']['key']['#states']['required'] = [
+    $form['field_storage']['subform']['settings']['allowed_values']['table'][0]['item']['key']['#states']['required'] = [
       ':input[name="field_storage[subform][list_predefined_options_plugin_id]"]' => ['value' => ''],
     ];
-    $form['settings']['allowed_values']['table'][0]['item']['label']['#states']['required'] = [
+    $form['field_storage']['subform']['settings']['allowed_values']['table'][0]['item']['label']['#states']['required'] = [
       ':input[name="field_storage[subform][list_predefined_options_plugin_id]"]' => ['value' => ''],
     ];
 
@@ -65,9 +67,9 @@ function list_predefined_options_form_field_storage_config_edit_form_alter(&$for
     // it's not possible to change a field from a list option plugin to a custom
     // list of values.
     if (isset($settings['plugin_id'])) {
-      $form['settings']['allowed_values']['#access'] = TRUE;
+      $form['field_storage']['subform']['settings']['allowed_values']['#access'] = TRUE;
       // Also hide the warning about the hiding.
-      $form['settings']['allowed_values_function']['#access'] = FALSE;
+      $form['field_storage']['subform']['settings']['allowed_values_function']['#access'] = FALSE;
     }
 
     // If the list_predefined_options_plugin_id element is changed from a plugin
@@ -77,13 +79,13 @@ function list_predefined_options_form_field_storage_config_edit_form_alter(&$for
     // function, but by the time we get here, both the form state and the field
     // config entity see it as empty, probably because of our entity builder
     // having acted.
-    $allowed_values_function_setting = $field->getSetting('allowed_values_function');
+    $allowed_values_function_setting = $field_storage->getSetting('allowed_values_function');
     if (empty($allowed_values_function_setting) || $allowed_values_function_setting == 'list_predefined_options_allowed_values') {
-      $form['settings']['allowed_values']['#access'] = TRUE;
-      $form['allowed_values_function']['#access'] = FALSE;
+      $form['field_storage']['subform']['settings']['allowed_values']['#access'] = TRUE;
+      $form['field_storage']['subform']['allowed_values_function']['#access'] = FALSE;
     }
 
-    $form['#entity_builders'][] = 'list_predefined_options_form_field_storage_config_edit_form_builder';
+    $form['field_storage']['subform']['#entity_builders'][] = 'list_predefined_options_form_field_storage_config_edit_form_builder';
   }
 }