Shortlink doesn't show on admin bar

I’ve successfully installed WordPress 3.1.3 on several sites but for some reason on one of them the “Shortlink” item does not appear on the menu bar (when on single post pages).

Also, this code which is hooked onto admin_bar_menu and works elsewhere does not work on the same site:

global $wp_admin_bar;
$current_object = get_queried_object();
if ( empty($current_object->post_type) )
{
    $wp_admin_bar->remove_menu('edit');
}

(This code removes the “Edit” menu item if not on a single page)

Any ideas why these two things would’nt be working? Thanks in advance.