LAVROFF

Hello. Sorry if this topic repeats but i can't find a solution. If i disable "file manager" rights from a user but this user created a subuser and gives him rights for file manager, subuser is allow to use file manager. It is possible to set rights on users-->subusers but user can change it back. So if i don't want anybody have an access to file manager it is possible to bypass it just crearing subuser and giving him file manager access rights. Is there any solution? Sorry for my english. Hope you understand what i mean.