How to test your mouse
Click inside the test area with each button: left, right, middle (press the wheel) and the two side buttons if your mouse has them. Each button lights up while it is held and counts every press. Scroll up and down to test the wheel.
The tester also watches for chatter: two presses of the same button closer together than the threshold you set. That is the classic sign of a worn switch that double clicks on its own.
Common mouse problems
A button that never lights up is not being detected at all: try another USB port or check the mouse software. A button that counts two presses for one click has a bouncing switch. A wheel that jumps the wrong way usually has a dirty or worn encoder.
FAQ
Why does right click open a menu?
It does not inside the test area: the menu is blocked there so right clicks can be counted.
Does this work for touchpads?
Yes. Taps and two-finger clicks are detected as left and right clicks.