The editor uses a plug-in system, using dlls. One of them is a preview plug-in, that of course will display a terrain representation of the heightfield values.
The gl preview dll runs in the same process as the main program, but it creates a window for the output, and then creates a message handling thread, that just sits in a loop polling for messages. That all works fine, messages are getting through, the window gets made etc..
The problem is that OpenGL fails to start up. ChoosePixelFormat fails, and GetLastError returns 50, which using the error lookup utility means:
"The network request is not supported."
Which, needless to say makes no sense. The code itself works fine, since it comes cut and paste from a working OpenGL program, and comparing the code, they are identical.
I thought there may be some sort of weird TNT issue where you couldn't have both types of programs active, but that isn't the case, anyone know if you can't use both in the same process?