Yesterday, I thought I'd give blackbox a try out. It's been a while.
Anyway, I found that whichever workspace I switched to, the label in the toolbar always stated "Workspace 1". I found someone had reported it in 2009 on sourceforge and attached a modified Screen.cc, but nobody has responded to it.
I've made and tested a very small patch from that Screen.cc and so far it works with no problems. Better call it experimental though
*edit: This is for version 0.70.1
Cheers