How to make the invisible menu

I already had the Re-attach feature in a plugin of mine and am shamelessly copying your unattach functions.

It’s good practice to secure all our actions. This is what I did:

In the column display use this URL

$url_unattach = wp_nonce_url(
    admin_url( 'admin.php?page=unattach&noheader=true&post_id=' . $post->ID ),
    'my_nonce_name'
);

And in the submenu callback, put this at first

check_admin_referer( 'my_nonce_name' );

It’s a pity that bulk actions can only be removed . I’ll report back if I have any suggestions on this.

cheers!

Ok, final touch. You don’t need to check for is_admin() in the following, one because it’s already targeting upload.php and the other is already an admin_* action and can be targeted as well:

add_action( 'load-upload.php', 'bulk_action') );
add_action( 'admin_footer-upload.php', '_admin_footer') );