Index: wp-admin/nav-menus.php
===================================================================
--- wp-admin/nav-menus.php	(revision 18873)
+++ wp-admin/nav-menus.php	(working copy)
@@ -432,9 +432,9 @@
 if ( is_nav_menu( $nav_menu_selected_id ) )
 	$edit_markup = wp_get_nav_menu_to_edit( $nav_menu_selected_id  );
 
-function wp_nav_menu_max_depth() {
+function wp_nav_menu_max_depth( $classes ) {
 	global $_wp_nav_menu_max_depth;
-	return "menu-max-depth-$_wp_nav_menu_max_depth";
+	return "$classes menu-max-depth-$_wp_nav_menu_max_depth";
 }
 
 add_action('admin_body_class','wp_nav_menu_max_depth');