For the past few weeks now my mouse has been working erratically. Often (though not always) when I single-click the mouse, the system behaves as if I double-clicked it. It seems to happen instantaneously, faster than a person could even get the second click in there. This is incredibly frustrating. When I want to select something, the system responds by launching it. If I'm in a large spreadsheet and I hit the scrollbar once to go forward, the system behaves as if I clicked twice and advances two pages. I've seen some info on this problem here but no solutions yet. Anyone have a fix? This seemed to start around the same time I ran an automatic Apple upgrade, but that could be coincidence.