trouble with winviz.exe

[farshizzo]

The problem with the exception will be fixed in the next release. Either way, you should usually use the is operator when checking for equality with None

if textureSet[slotToReplace] is None:

I'm not sure what is causing winviz to hang. Are you making sure that your threads cleanup properly before your script exits? Can you create a small script that recreates the problem?