im having this same problem...have you figured it out yet?
I figured it out.
You can change gamma/brightness/contrast in the UT2003.ini under [WinDrv.WindowsClient] or you could do it in the editor under View/Advanced Options/Display.
And I guess you could even do it in game.
This was never a problem for me in the past up till I intalled the new nvidia drivers for my lappy...
Ok maybe what I just said is not correct.
If I right click on the minimize/maximize button at the bottom of the screen it goes from normal back to glitchy very bright.
But if I left click and then drag on the bar into the editor (in a blank area) the brightness stays normal!
So I guess the real solution is to trick into staying the same?
I think this may have to do with directx 9.a....
this is a REALLY late reply, so sue me.
Ive discovered the same thing, fullscreen playing allows gamma adjustments, windowed playing does not.
It is, ive also discovered, a result of directx 9.
Ive been using a little utility called gapa (gamma panel) to do on the fly changes before i start playing. Unfortunately, its a bit buggy, changing settings results in it being broke, BUT, if you can get it to work, its MUCH less bloat then powerstrip or anything else out there.
If anyone has any ideas, or can reccomend SMALL non-bloated apps that can accomplish that, i would be interested in hearing them.
Prob someone will correct me if i`m wrong?
but the brightness of the gamma is set by the brightness in the game.
a lot of mappers wanted it that way so they know the lighting they have done would be the same when playing there map in ut2003.
if you lower the brightness in the game,the editor/desktop wont be as bright.
another thing you can do is add -nogamma at the end of the shortcut on UT2003 Editor.
I dont like the way it`s does that,but for the great mappers they love it.