It’s been my experience that the double-click problem is caused by the contacts in the microswitch getting dirty/oxidized. Usually, cleaning them will fix the problem for a while, maybe a few months, before it inevitably happens again. Supposedly this happens more frequently with cheap microswitches from China than with better quality ones from Japan, but I don’t have enough personal experience to say whether this is true. I do know that the area that actually makes contact is smaller than the head of a pin, so it doesn’t take much to make that connection unreliable. Typically, as well as accidentally double-clicking, you’ll see the left button randomly ‘let go’ while you’re dragging something. Most mice use microswitches that look like this; You can pop them open by inserting the tip of a knife into the edge of that little latch between the two holes and gently prying it off the catch. Then do the same to the other side. Be careful not to lose the TINY button! Some microswitches have the catches on the...