diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index a6b47f9c17..9d0e156630 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -1523,11 +1523,7 @@ function wp_ajax_save_widget() {
 	 */
 	do_action( 'widgets.php' );
 
-	/**
-	 * Fires early when editing the widgets displayed in sidebars.
-	 *
-	 * @since 2.2.0
-	 */
+	/** This action is documented in wp-admin/widgets.php */
 	do_action( 'sidebar_admin_setup' );
 
 	$id_base = $_POST['id_base'];
diff --git a/wp-admin/widgets.php b/wp-admin/widgets.php
index b861b38928..9383d7436c 100644
--- a/wp-admin/widgets.php
+++ b/wp-admin/widgets.php
@@ -35,7 +35,8 @@ if ( 'on' == $widgets_access ) {
 }
 
 /**
- * Fires early before the Widgets administration screen loads, after scripts are enqueued.
+ * Fires early before the Widgets administration screen loads,
+ * after scripts are enqueued.
  *
  * @since 2.2.0
  */
diff --git a/wp-includes/class-wp-customize-widgets.php b/wp-includes/class-wp-customize-widgets.php
index 3a1321098f..c76425f46e 100644
--- a/wp-includes/class-wp-customize-widgets.php
+++ b/wp-includes/class-wp-customize-widgets.php
@@ -281,6 +281,8 @@ final class WP_Customize_Widgets {
 	public function customize_controls_init() {
 		do_action( 'load-widgets.php' );
 		do_action( 'widgets.php' );
+
+		/** This action is documented in wp-admin/widgets.php */
 		do_action( 'sidebar_admin_setup' );
 	}
 
@@ -1158,6 +1160,8 @@ final class WP_Customize_Widgets {
 
 		do_action( 'load-widgets.php' );
 		do_action( 'widgets.php' );
+
+		/** This action is documented in wp-admin/widgets.php */
 		do_action( 'sidebar_admin_setup' );
 
 		$widget_id = $this->get_post_value( 'widget-id' );