@kamimatsu: (part 2) It also happens in games, for example, if I'm playing Fallout 4 like I have recently, I'll click to sell something, and it will also sell the item that was just underneath the one I wanted to sell.

Plus firing semi-autos twice.

@zenitix: I have a similar problem where it clicks on its own. I use a touchpad and sort of unlearned the mouse. Have to disable tapping and use the buttons. Are you using Windows? My issue started with Windows 7. I had no issue with any version of Linux