Firefox does not support scrollable divs with the mouse wheel.
I poked around in the extensive bug database trying to find this listed, but the
number of bugs is just too daunting. This really sucks, because we develop our
stuff to work on ie as well as Firefox, so whenever we run into a div with a
scroll bar, the screen just kind of jumps around. I'm surprised that I haven't
heard much about this problem from other people, as the mouse wheel has become
invaluable to me, I hate having to move my mouse to the scroll bar, and manually
move it down......