How do I run X apps from another login?

[SkyHigh]

The other day I was logged in as my standard user running X and I discovered I needed to change some parameters in a file under /etc. I su'ed to root and cd'ed to /etc. I then tried to open the file using my favourite graphical editor -- Nedit -- but it returned an error telling me that I coudln't open it beacuase I was logged into X as another user.

I just used vi in the end to edit the file, but it made me curious whether this is possible or not?

Thanks,

SkyHigh

[Molecule Man]

From an xterm su -
then give the command line startup like:
nedit /etc/foo

The dash is important.