Ticket #39665: 39665.2.diff

src/wp-includes/class-wp-customize-nav-menus.php

@@ -1132 +1132 @@
                 add_action( 'wp_enqueue_scripts', array( $this, 'customize_preview_enqueue_deps' ) );
                 add_filter( 'wp_nav_menu_args', array( $this, 'filter_wp_nav_menu_args' ), 1000 );
                 add_filter( 'wp_nav_menu', array( $this, 'filter_wp_nav_menu' ), 10, 2 );
+                add_filter( 'wp_page_menu', array( $this, 'filter_wp_nav_menu' ), 10, 2 );
                 add_filter( 'wp_footer', array( $this, 'export_preview_data' ), 1 );
                 add_filter( 'customize_render_partials_response', array( $this, 'export_partial_rendered_nav_menu_instances' ) );
         }
@@ -1294 +1295 @@
          * @return null
          */
         public function filter_wp_nav_menu( $nav_menu_content, $args ) {
+                $args = (object) $args;
                 if ( isset( $args->customize_preview_nav_menus_args['can_partial_refresh'] ) && $args->customize_preview_nav_menus_args['can_partial_refresh'] ) {
                         $attributes = sprintf( ' data-customize-partial-id="%s"', esc_attr( 'nav_menu_instance[' . $args->customize_preview_nav_menus_args['args_hmac'] . ']' ) );
                         $attributes .= ' data-customize-partial-type="nav_menu_instance"';

src/wp-includes/js/customize-preview-nav-menus.js

@@ -212 +212 @@
                                 } else if ( partial.params.navMenuArgs.theme_location && api.has( 'nav_menu_locations[' + partial.params.navMenuArgs.theme_location + ']' ) ) {
                                         menuId = api( 'nav_menu_locations[' + partial.params.navMenuArgs.theme_location + ']' ).get();
                                 }
-                                if ( ! menuId ) {
+                                if ( ! menuId && ! partial.params.navMenuArgs.fallback_cb ) {
                                         partial.fallback();
                                         deferred.reject();
                                         return deferred.promise();