Under Debian, I could su to root in a console, and launch gparted from the CLI.

Now, I get:

ron@ron:~/Desktop $ su
Password:
No protocol specified
xmodmap: unable to open display ':0.0'
No protocol specified
xmodmap: unable to open display ':0.0'
No protocol specified
xmodmap: unable to open display ':0.0'
No protocol specified
xmodmap: unable to open display ':0.0'
No protocol specified
xmodmap: unable to open display ':0.0'
No protocol specified
xmodmap: unable to open display ':0.0'

root@ron:/home/ron/Desktop # gparted
No protocol specified

(gpartedbin:4721): Gtk-WARNING **: cannot open display: :0.0

What did I do wrong ?

And by the way, logging in under xdm (?) I had a shock when the Debian name and loogo appeared on the login screen...

Cheers,

Ron.
-- 
           As a computer, I find your faith in technology amusing.

                   -- http://www.olgiati-in-paraguay.org --