Test mouse side buttons and the scroll-wheel click
Check mouse side buttons and middle click while separating browser navigation, remapped controls and scroll movement from actual button input.
A side button that doesn’t light up in a browser test isn’t automatically broken. It may be mapped to a keyboard shortcut or handled by the browser as navigation. The useful question is which event the computer receives when you press that particular control.
Use the interaction area
Open Mouse Tester and keep the pointer inside its test pad. Press and release one button at a time. The tester records button input in that area and attempts to prevent normal context-menu and auxiliary-click actions from interfering.
Start with the primary button so you know the pad has your input. Then try the secondary button and wheel click before moving to the side buttons. A deliberate sequence makes it easier to identify which physical control produced each response.
Separate the wheel’s two jobs
Turn the wheel forward and backward. Watch the scrolling counters rather than expecting a button indicator to light up. Then press the wheel straight down without turning it and look for middle-button input.
A wheel can turn normally while its separate click mechanism fails or feels inconsistent. Conversely a working middle click doesn’t establish that the scrolling encoder is behaving correctly. If scrolling jumps in the wrong direction then use the scroll-wheel troubleshooting guide.
Understand labels and mappings
The browser reports logical button values. The usual assignments include the primary button and auxiliary controls but operating-system settings can change how physical buttons map to those values. MDN documents these button values.
If you use a left-handed configuration then don’t diagnose a fault just because a physical side differs from a label you expected. Compare the mapping with your system settings and record the response that actually appears.
Investigate a missing side-button response
If pressing a side button moves back a page then navigation intercepted the test. Return to the tester and confirm the pointer was inside the pad. Don’t interpret the accidental navigation as a silent switch because an action did reach the browser.
If nothing visible happens then inspect your mouse software’s current profile. A button assigned to a keyboard shortcut may produce keyboard input instead of a mouse-button event. Test the assigned action in an appropriate harmless context or temporarily select a standard mapping after recording the original setting.
A DPI switch can change sensitivity inside the mouse without sending a separate event to the page. Some extra controls therefore can’t be identified by a browser mouse-button display.
Compare repeatable actions
Try several deliberate presses at a normal pace. Note whether a control sometimes misses or produces an unexpected extra response. Rapid clicking is a different test and can obscure a simple mapping check.
If a button is unreliable across applications with an ordinary mapping then compare another connection or computer where practical. Keep the same physical action and note any change. A useful fault report identifies the button and observed behavior rather than relying only on a test-page color.
Don’t open the mouse merely because one browser label stayed dark. Resolve mapping and interception questions first.
Common questions
Are scrolling and middle click the same input?
No. Turning the wheel produces scrolling while pressing it down is usually a separate button. A mouse can scroll correctly even when its wheel-click switch doesn’t register. Test both actions independently.
Why does a side button move back a page?
Browsers commonly assign navigation to additional mouse buttons. Use the tester’s interaction area but recognize that browser or device software can still intercept an action before the page handles it.
Can the tester see every button on a gaming mouse?
Not necessarily. Some buttons change a device setting internally or are remapped to keystrokes. A browser page can only report the input that reaches it rather than every physical switch on the shell.