main folder cleaned?
I already cleaned my Radiant, still same problem.
Edit: And I have already reinstalled.
The screenshot is Win7?
Then XP and 7 doesn't work, so it might be the hardware, but did it work before on the current hardware?
timescale 0.01
Idk, try Misc - Color - themes
kung: It's Windows 8, not Windows 8.1. On Windows 7 it worked (old PC), But as I bought this computer (Windows 8) it does worked, but yet not anymore.
pollo: I tried it. Still doesn't work, but thanks.
I have the same issues with Maya 6.0, the Viewport just turns to the default clear color (gray) when its not "focused".
Try to run it in Compatibility Mode for Win 7 e.g. (though that doesn't works for me on Maya, but worth a try).
timescale 0.01
Hey Loveboy, try to move around the window sizes in radiant, not the application window but the sizes of different areas like 3D area, 2D area, textures, etc.
Lool, this definitely doesn't look right, I would advice you to reinstall radiant, but make sure that you delete all the files from Bin folder before installing it again, sorry but can't access mod tools right now so idk which file is exactly the one that stores radiant configuration.