Start with the symptom
A physically stuck key may feel slow, uneven, or remain depressed. A logically stuck key can look normal while the operating system behaves as if it is still held. These symptoms need different tests.
Check what the browser receives
- Open the keyboard tester, start the test, and press then release the suspect key once.
- Watch the held-key area. A normal release should remove the key immediately.
- Repeat without switching tabs or opening a browser shortcut.
- If the browser window loses focus, repeat the test; Keyboard Check Lab intentionally clears held-key state after a focus loss to avoid a false warning.
- Test in a plain text editor. If the symptom appears outside the browser, the cause is less likely to be webpage focus handling.
Check software before hardware
Disable remapping tools, gaming profiles, macro utilities, remote-desktop software, and accessibility features only long enough to test. Record the original settings first so they can be restored. Restarting the computer can also clear a transient input state.
Inspect the physical key safely
Disconnect the keyboard. Look for a tilted keycap, visible debris, or resistance that differs from neighboring keys. Do not pry low-profile or laptop keycaps without model-specific instructions; their retaining clips are easy to break.
Escalate with evidence
If the same key remains active across applications and computers, note the model, connection type, firmware version, and reproduction steps. That record is more useful to support than a browser screenshot alone.