Keyboard release events missing after browser restart

You release a key, but a website or browser game still acts as if you are holding it. Restarting the browser may clear the problem, but that does not tell you whether the keyboard, browser, or original website caused it.

Test the keyboard before and after restarting the browser. The Keyboard Test can show whether keys register and how many work at once. It is useful for checking input, but it is not a log of every key press and release event.

Check the key before and after a restart

Open the Keyboard Test in the browser where you noticed the problem.
Press and release an ordinary letter key, such as A. Watch the test's response as you press, then lift your finger completely. If the display shows a key state, check whether it returns to normal.
Repeat with the key that seemed stuck. Try it several times, pressing briefly and then holding it for about two seconds before releasing.
Close the browser completely, not just the tab. Open it again and return to the test. Repeat the same key checks.
If the tool supports simultaneous key input, press two ordinary keys together, then release them one at a time. This can help separate a single-key problem from an issue that appears during combinations.

Use the same keyboard and the same browser both times. If you have an external keyboard, test it separately from the built-in keyboard. Avoid using Fn, the Windows key, Print Screen, and laptop shortcut keys for this check. The operating system usually handles them before a browser page can receive them.

What the result means

The key registers and the display clears after release

The browser test is receiving the key input normally. The original website or game may have kept its own held-key state after losing focus. Reload that page and check whether the problem returns. If it happens only there, the keyboard itself is less likely to be at fault.

The key registers, but its display appears stuck

This can point to a missed release, but it is not proof of a hardware fault. A page may stop receiving input when it loses focus, or its display may fail to update. Click back into the test, release all keys, and check again. If the same key stays active in a fresh test page, continue with the fixes below.

The key does not register after the restart

A browser restart does not repair a key that is not sending input. Check whether the key works in another browser or in a plain text field, then compare it with another keyboard if one is available. If only the original website misses the key, check its focus and settings rather than assuming the keyboard is broken.

Only shortcuts or function keys behave differently

Some keys and key combinations are handled by the operating system before the browser sees them. The Fn key never reaches the browser, and the Windows key, Print Screen, and common brightness or volume shortcuts are usually intercepted. A browser test cannot confirm how those keys behave inside the operating system.

How to fix a key that stays active

Release the key and restore focus. Click the test page, let go of every key, and press the problem key once more. If the issue happened after switching to another window, the original page may have missed the release while it was unfocused.
Check for a physically stuck key. Look for a keycap that sits lower than its neighbors or does not spring back. With a laptop, do not pry off a keycap unless the manufacturer says it is removable. If a key feels sticky, power off the device and follow its cleaning instructions.
Check accessibility keyboard settings. On Windows 11, open Settings › Accessibility › Keyboard and review Sticky Keys and Filter Keys. On macOS, open System Settings › Accessibility › Keyboard and review Sticky Keys and Slow Keys. These features change how some key presses are handled. Turn off a setting only if you do not rely on it.
Disconnect and reconnect the keyboard. For a USB keyboard, try another port and connect it directly instead of through a hub. For a wireless keyboard, check its battery, reconnect its receiver, or pair it again.
Compare with another browser. Run the same key checks in a second browser. If the problem appears in just one, update or reset that browser's settings and temporarily disable extensions that change keyboard input.
Restart the computer. If the issue affects multiple browsers or apps, a computer restart can clear a system-level input problem that closing the browser cannot.

When the keyboard may be faulty

If the same physical key sticks or fails in multiple browsers and applications, test another keyboard on the computer. If the other keyboard works normally, the original keyboard or its connection is the likely cause. An external keyboard with a bad switch may need repair or replacement. For a built-in laptop key, contact the manufacturer or a repair shop, especially if the key became sticky after a spill.

If several keys fail together, the problem may involve the keyboard connection or its internal key matrix, rather than separate damaged keys. A browser test can identify which inputs behave strangely, but it cannot inspect the keyboard's circuitry. See how to check a key that stays pressed for more signs of a physical or system-level fault.

Why restarting changes what you see

Browsers send a page separate events when a key goes down and when it comes back up. If a page loses focus while a key is held, it may not receive the release event. A well-behaved page should clear its held-key state when focus is lost, but some games and web apps do not handle that situation correctly.

Closing the browser removes the old page and its in-memory state. The new page cannot replay a release event that the old page missed. If the problem disappears after a restart but returns on one website, that points toward how the website tracks held keys. If it continues in the Keyboard Test and other apps, check the keyboard and system settings instead.

The Keyboard Test checks browser-visible key input, not every key event the operating system or another app receives.