I don’t know where this error has come from; I’ve never encountered it before. Basically, the model viewing portion of the model browser in Hammer is completely invisible. I’ve tried reinstalling twice, and deleting the registry keys with it as well. Oddly enough, the Portal 2 Authoring Tools are fine (I can see models no problem), but with L4D, it just doesn’t work.
Here’s a picture describing my problem: