I wanted to use Xnest to create a safe environment for selenium browser tests. But I can't start it:
> Xnest -geometry 1200x1000+0+0 Fatal server error: Server is already active for display 0 If this server is no longer running, remove /tmp/.X0-lock and start again.
Well, duh: My X server is running on display 0. Since Xnest needs a running X server to work at all, the error message seems kind of odd.
How do I start Xnest correctly?