Admin - Custom Post Type in WooCommerce menu - how to control menu order

Question

I'm using WordPress 4.9.1 and WooCommerce 3.2.6.

I have added a new Custom Post Type (Subscriptions) and inserted the menu item under the 'WooCommerce' menu in the admin panel using 'show_in_menu' => 'woocommerce', but I want to move my post type immediately under 'Orders'.

I have tried changing menu_position but it doesn't have any effect.

register_post_type('subscription',
    array(
      'labels' => array(
        'name' => __( 'Subscriptions' ),
        'singular_name' => __( 'Subscription' ),
        'add_new_item' => "Add New Subscription",
        'edit_item' => "Edit Subscription",
      ),
      'public' => true,
      'has_archive' => false,
      'publicly_queryable'  => false,
      'show_in_rest'       => false,
      'show_in_menu'       => 'woocommerce',
      'menu_position'      => 9999,
      'supports' => array(
          'title',
          'revisions'
      )
    )
);

SOLUTION:

I changed show_in_menu to false when registering my post type, and added the following code:

function add_subscriptions_menu() {
    add_submenu_page('woocommerce','Subscriptions','Subscriptions', 'manage_options', 'edit.php?post_type=subscription');
}

// Change the 30 to customise item's order within WooCommerce submenu.
add_action( 'admin_menu', 'add_subscriptions_menu', 30 );

Answer 1

menu_position is not used when you set show_in_menu to a submenu.

to put your menu in last position there is 2 solutions. The first is to change the menu construction priority like this :

add_action("admin_menu", function () {

    remove_action('admin_menu', '_add_post_type_submenus');

    add_action( 'admin_menu', '_add_post_type_submenus', 200);
    // 200 to set it after the last element of WooCommerce which as the priority 70

}, 1);

With this, all custom post types are modified. If this is not what you want, the 2nd solution is to set show_in_menu to FALSE and to create the submenu by yourself with https://developer.wordpress.org/reference/functions/add_submenu_page/