Global navigation issue

Hi everyone,

I am having a small issue and don’t know how to fix it. In functions.php I’ve pasted

add_action('init', 'register_custom_menu');
function register_custom_menu() {
register_nav_menu('custom_menu', __('Custom Menu'));
}

But there seems to be an issue when I go to appearance, then menus. The menu I create does not update the Global Nav. It just stays the same. Here is functions.php’s code.

Please help and thank you.