Hi Ian,

Ah, the driver might be where the difference is. I am using PyOpenGL 3.0.1 but I'm on a Mac, so I'm not using the NVIDIA drivers at all.Best,

I sent a bug report to NVIDIA, but evidently I have to be a registered developer to submit anything so technical.  I started the application process, so hopefully they'll be able to get the report in a few days.  Let me know how your tests go,

Sorry for the delay, I was really busy last week. I tried the script on Linux and, much to my surprise, I still can't reproduce the problem you describe.

I initially get a red quad and then I can turn on and off the white quad without any issues.

This is my system configuration, I'm on Fedora 12 x86_64:

>>> glGetString(GL_VERSION)
'4.0.0 NVIDIA 256.44'

>>> glGetString(GL_RENDERER)
'GeForce GTX 465/PCI/SSE2'

>>> glGetString(GL_VENDOR)
'NVIDIA Corporation'

I'm starting to wonder whether this could be a Windows-specific issue.