Mouse scrollwheel scrolls many lines- but only Firefox

Question

What I have: Latest Firefox browser with Windows 10 on a Dell laptop, and a Bluetooth mouse with a scroll wheel. In Windows Settings, the scroll value is set to 3. ("Choose how many lines to scroll each time")

What I see:

• Moving the scroll wheel works as expected everywhere except in Firefox.
• In Firefox, all content (web page, text areas, sidebars, etc.) scrolls more than 60% of the entire screen height. This makes scrolling with the mouse almost entirely useless.
• Sometimes Firefox suddenly works as expected, and I see no pattern in when that happens. For instance, I was working in another tab just now and scrolled; I decided to post here about it and opened a new tab. While composing this text, I notice that the scrolling works correctly ... for now, anyway. Notice that I didn't reboot nor even restart the browser!

What I want: Firefox must always obey the scroll-wheel settings.

Answer 1

1. In Firefox Settings, in the search box at top, type scroll. Try changing the settings for Use autoscrolling and Use smooth scrolling to see if that fixes the issue.
2. In about:config, search for scroll. Look for any nonstandard value, i.e. any shown in boldface. Click on the Revert button to the right of the value to reset it to the default, unless you know why that value had been changed.

On the machine on which this is being typed, in Firefox,

• Use autoscrolling and Use smooth scrolling are both checked.
• All values are default in the entire list shown for scroll.

Also try running Firefox in Troubleshoot Mode to see if an extension is causing the issue.