Test mouse input through a hub before an interview

Your mouse may work fine on the desktop but skip clicks or scroll unevenly when it is connected through a dock or USB hub. Before a live coding interview, test the mouse in the same setup you plan to use, then compare it with a direct connection.

The Mouse Test checks the buttons, scroll wheel, double-click behavior and polling rate in your browser. It can help you find out whether the trouble follows the mouse, the hub or the interview app.

Test the mouse through the hub

1. Connect the mouse to the hub and open the Mouse Test. Keep the mouse on the surface you expect to use during the interview.
2. Click each mouse button several times, including the middle button if your mouse has one. Check that each click registers once, and that holding a button while moving the mouse does not interrupt the drag.
3. Scroll slowly and then more quickly in both directions. Watch for skipped, reversed or uneven movement. Try the double-click check as well, using the same pace each time.
4. Check the polling rate reading, then repeat the button and scroll checks with the mouse connected directly to the computer. Keep the same browser, surface and mouse position so the hub is the main thing that changes.
5. Switch back to the hub and repeat the test once. A single missed click can be accidental, but a repeatable difference between the hub and direct connection is useful evidence.

If you use a wireless mouse, test with its receiver in the hub as well as directly in the computer. Keep the receiver in the same general location for a fair comparison. A hub can change the receiver's distance from the mouse or place it beside other electronics.

What the result means

Clicks and scrolling work the same through either connection

The browser is receiving the mouse input consistently in both setups. That is a good sign for ordinary coding tasks such as selecting text, clicking controls and scrolling. It does not test the interview platform itself, so try that platform's own practice room or sample task if one is available.

Input skips only when the mouse uses the hub

The mouse, hub, cable or receiver connection is a likely cause. Try another port on the hub, then connect the hub to a different computer port. If the issue disappears when the mouse is plugged directly into the computer, use the direct connection for the interview or replace the suspect hub or cable.

The same problem happens with and without the hub

The hub is less likely to be responsible. Check the mouse, its cable or wireless receiver, the battery if it is wireless, and the surface. You can also test with another mouse to see whether the problem follows one device.

The polling rate changes, but clicks and scrolling feel normal

Polling rate is how often the mouse reports its position to the computer. A browser reading can vary with the mouse, connection and system load. A different number by itself does not prove that the hub is adding noticeable delay. Prioritize missed clicks, interrupted dragging or unreliable scrolling over a small reading change.

The test is smooth, but the interview app still feels delayed

The browser test checks that mouse input reaches the page. It cannot measure every part of a remote desktop or interview platform. If the mouse works normally here but feels delayed in a remote session, check that app separately. For that case, see how to check mouse input over a remote desktop.

How to fix mouse problems through a hub

1. Reconnect the mouse and hub. Unplug the mouse, then the hub, and reconnect them firmly. If the hub has a detachable cable, reseat that too. Avoid moving or flexing the cables while you test.
2. Try another hub port. A single port or connector can be loose or damaged. If the hub has a power adapter, make sure it is connected securely.
3. Reduce devices sharing the hub. Temporarily unplug storage devices and other accessories, then test the mouse again. A mouse uses little bandwidth, but a faulty hub, cable or power connection can still disrupt connected devices.
4. Move a wireless receiver closer. Use a short USB extension cable if you have one, or plug the receiver directly into the computer. Keep it away from busy USB 3 devices and metal objects, and replace or recharge the mouse battery.
5. Check pointer settings. In Windows 11, open Settings › Bluetooth & devices › Mouse and check the pointer speed and scrolling options. On a Mac, open System Settings › Mouse and check tracking and scrolling settings. Restore a comfortable setting if it changed unexpectedly.
6. Restart and test again. Restart the computer, reconnect the same setup and repeat the comparison. If the mouse still fails only through the hub, use a direct port for the interview or test another hub.

When the hub or mouse may be faulty

If the problem follows the hub across multiple ports or computers, while the mouse works reliably when connected directly, the hub or its cable may be failing. If the problem follows the mouse even when connected directly, test another mouse on the same computer. Replace a faulty accessory or contact the maker if it is under warranty rather than relying on an unreliable connection during the interview.

The test runs in your browser and checks the mouse connected to the device you are using.