As a workaround you can try this command which give access to your X session to root: xhost +
I don't know how to make this permanent, I am researching a similar bug. If you find a solution please do report it here. -- kdesu does not respect NOPASSWD from sudoers https://launchpad.net/bugs/78640 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs