remove duplicate name submenu link from the custom post type

Question

I was wondering what would be the proper way to remove submenu with duplicate name in custom post type in the admin. I tried to use remove_submenu_page() however since its a duplicate it is showing same slug for menu and submenu /wp-admin/edit.php?post_type=portfolio and to use that function my understanding slugs should be different

Answer 1

The following code seems to work and remove duplicate name from Porfolio custom post type

'all_items'     => __( '' )