su/sudo cannot X

[Lei Kong <lei.kong@gmail.com>]

Hi,

I have a strange problem with my thinkpad z60t, running debian testing.
I ran these commands in konsole or xterm under kde:

$xhost +
$ sudo -s
#kedit 
kedit: cannot connect to X server

What is wrong?
My desktop runs debian testing too, but after su or sudo,
root can open windows even without xhost +.

xserver-xorg                 6.8.2.dfsg.1-11
sudo                             1.6.8p12-1
kdebase                       3.4.3-3

Can someone enlighten me?

Thanks.

Lei Kong