Victor, the Ubuntu Desktop administration tools are specifically designed to use sudo instead of su, i. e. authenticate with the user's password and ignore the root user completely. Thus this is by design and not a bug.
-- Fails to authenticate critical Administation tools like Networking, Services, etc https://launchpad.net/bugs/5100 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
