Finding a double-click fault (chatter)
When the switch inside a mouse button wears out, one press can bounce and register twice. This is called switch chatter, and it opens files you meant to select and breaks drags.
This test counts a suspect double click whenever the same button fires again within the threshold (80 ms by default). Click slowly, one press at a time, 20 to 30 times. If the suspect count rises, the switch is the likely cause. Deliberately fast clicking can trip it even on a healthy mouse, so go slowly.
What polling rate means
Polling rate is how often the mouse reports movement to the computer. 125 Hz means 125 times a second (every 8 ms) and 1000 Hz means 1000 times a second (every 1 ms); higher rates deliver movement in finer steps. Gaming mice usually let you change it in their own software.
Chrome and Edge provide raw pointer events, which give a reading close to the real rate. Other browsers only expose events grouped per screen frame, so the estimate can read low. Slow movement gives the mouse little to report, so move it quickly in circles while measuring. Wireless mice may also drop their rate in power-saving mode.
Wheel and side buttons
On a regular notched wheel, each notch should add exactly one to the count. Several counts per notch or counts in the wrong direction suggest a dirty or worn wheel encoder. Back and forward side buttons cannot navigate away from this page while you are inside the test area, so press them freely. Mouse sensitivity (DPI) cannot be measured reliably in a browser, so it is not covered here.