changing user with SU, gives "Xlib: connection to ":0.0" refused by server"

[Mario Vukelic]

On Mon, 2007-10-08 at 13:01 -0300, Derek Broughton wrote:
> 
> otoh, I routinely use sudo, get those messages, and apps still work as
> expected anyway!

You were lucky. Using sudo for X apps can be bad, something with
permissions in /var/temp or /var/lock or similar. It can prevent
non-root users from starting the app.

https://help.ubuntu.com/community/RootSudo#head-0c932eb3f1619126fc8307ee7690f462552d34ec