Why mice start double-clicking
Inside a mouse button is a small metal switch. When it is new, one press gives one clean signal. As it wears, or when dust and oxidation get in, the contact can bounce: a single press makes and breaks the contact several times, and the mouse may report two clicks instead of one. You notice it when a single click opens a file, drag-and-drop lets go mid-drag, or a single shot in a game fires twice.
How to use the checker
- Click slowly. Press the button once, let go, wait a moment, press again. You want single clicks, not speed.
- Watch for red. If one press shows up as two clicks only a few milliseconds apart, it is flagged. A human cannot press twice in 10 to 30 ms on purpose.
- Test every button. Left, middle and right are counted separately, so you can tell which switch is failing.
- Adjust the limit. The slider sets what counts as suspicious. 80 ms is a sensible default; lower it if you click quickly by habit.
If your mouse fails
- Check the mouse software for a debounce setting; a slightly longer debounce often hides a bouncing switch.
- Try another USB port and a different surface to rule out connection problems on wireless mice.
- If it is under warranty, the double-click fault is a common reason for a replacement. Switches can also be replaced by someone handy with a soldering iron.
