WordPress menu deletes when trying to add a hook
I don’t think there’s wp_nav_menu action. Perhaps you want the wp_nav_menu filter (doc)? function custom_novice_menu($args) { if( ‘primary’ == $args[‘theme_location’] ) // only apply to the right menu { $args[‘container’] = ‘div’; } return $args; } add_filter(‘wp_nav_menu’, ‘custom_novice_menu’);