Editor doesn't work
From The DarkMod Wiki
Originally written by sparhawk on http://forums.thedarkmod.com/topic/1841
There are on some cards problems with the editor not working when anti aliasing is switched on.
From D3World: "For the wglMakeCurrent problem Simply remove AA before you start the editor."
Seems like some cards cannot have AA in windowed mode.
To resolve this problem you must edit DoomConfig.cfg:
set r_multiSamples "0"