Histogram not working in VirtualDub?

[Schlockmaster]

I'm using an ATI 600 USB on Windows XP with Vdub 1.9.11. I wanted to reference the histogram before starting captures to check levels but it never displays any information. Is there something specific that must be done for it to work, and is it even worth using the histogram in the first place? I've read conflicting opinions about its usefulness. To me it seems like a good idea to make sure highlights aren't blown out, etc. before capturing instead of trying to fix in post.