Double clicks: 0
Check your mouse buttons for a double click. Keyboard double click test is here.
Double clicks: 0
Double click is mainly a malfunction of a mouse, when the button you click one time makes two or more clicks instead.
Double click is very annoying if you didn't want it and happens in inopportune moments, so it's crucial to indicate it as soon as possible and fix.
This test is simple as potato: it measures time between clicks and if time is too short, it registers a double click with red signal.
For advanced users who know what they're doing there is a field hidden under the spoiler, where you can change time between clicks required to spot double clicks.
You can test here left, right and middle button for a double click.
Try to clean the insides of a mouse by disassembling it and blowing button with compressed air.
If cleaning does not help as a temporary measure you can try to adjust a double click time in Windows settings in Devices->Mouse->Advanced mouse settings (or something like that).
Advanced users can use special scripts in AutoHotkey software.
Hardware fix is to replace the defective button, it won't cost too much, if you can solder.
For majority of people double click is an issue. But for some crazy enthusiasts it's a glorious feature, which is hard to find. Yes, we are talking about Minecraft players (basically). Double clicking mouse can help players maintain high CPS in game with less effort than normal mouse.
The problem is, most of the mouse and keyboard companies try hard to eliminate such effect with different debounce technologies. And malfunctioning button is not an option here, because it cannot be offed when is needed.
The solution is to find a mouse with mechanical buttons and special proprietary software that allows to adjust debounce time. It's not an easy quest, but it can be done with some googling (some of the Glorious and Roccat mouses, for example).