First let me thank you for a great plugin - Nice implementation!
But I ran in to a problem. Im building a Multi Language site with WPML and in order to get the Language Selector Dropdown in the menu I have to add it via the PHP Filter wp_nav_menu_items.
The menu item works as expected in the regular (desktop) menu. But it doesn't show in the responsive menu.
It get the feeling that the responsive menu is generated before the wp_nav_menu_items filter.