My optical mouse rather suddenly lost its vertical scrolling ability. Computer virus? Nope. I plucked enough cat hair out of it to indicate that my damned cat should be bald. Must be a “critical mass” thing, because it worked fine up until it rather suddenly went, “pfffht.” Enough remained inside the mouse, unfortunately, that vertical scrolling remained erratic and annoying as hell.
Cats apparently grow fur as fast as they shed it, because Molly is far from being bald. A new mouse solved the problem, so she can begin killing this one now.