If you have enough saves, choosing "load saved mission" gives you a selection with a scroll bar. Fair enough... but if you scroll with the mouse wheel it spins the carousel, and dragging the scrollbar also drags the carousel.
It's not broken per se, just kind of annoying.
Actually, I think it's broken. There's a "thing" (very technical term) where a window is supposed to turn off UI interactions it intercepts. :)