Mouse wheel and sorting

This is the first time I've seen this and it is very nice. I'm using Mozilla Firefox and I noticed that I can drag the scrollbar and everything works, but when I use the mouse wheel only the scroll bar moves.

I also was under the impression that numbers in red meant negative -- if that is true, how come when the sorting by Market Cap. negative values are not sorted to the top for ascending or bottom for descending? How is the definition of negative values and sorting handled?