This is a truly terrible example of a user interface, and would've been fixed long ago except for the fact that with 3.x we had made the decision to stick with aD-derived code.
We no longer have to do that, if someone wants to add a clean and simple way to add a category from the bboard admin page go for it and submit your new pages and patches to Roberto.
Just remember that our major effort should be poured into 4x...this UI problem is so gross it demands a fix, but let's not get started with major 3.2 bboard redevelopment...
