Read lots of threads complaining about the MM, most related to gesture problems. So far I love the gestures; but I've not seen my problem listed. Every now and then, possibly once or twice every 30 minutes during heavy use, a routine left click will open the right click menu. The click is clearly on the left side. It will continue to produce the right click menu, but it seems that if I click on the very far left edge of the mouse that behavior will clear and it will return to normal left-sided use. I'm trying to figure out if this is just flakiness or if there might be something wrong with my mouse (that could result in a replacement). Everything else on the mouse works perfectly.