topic Re: Should scrolling with the Alt key held down perform history navigation by default? in Discussions

Should scrolling with the Alt key held down perform history navigation by default?

Botond — Fri, 24 Apr 2026 21:32:07 GMT

Hi!

We've recently received a Bugzilla report about Firefox's default behaviour when scrolling (either with mouse wheel or touch pad) with the Alt modifier key held down, which is to perform history navigation (that is, to go "Back" or "Forward" in the current tab's history).

The report pointed out that this can be easy to trigger accidentally, if you were e.g. performing a different keyboard shortcut that involves the Alt key (like Alt+Tab to switch between applications) and the key is still held down when you try to scroll.

This behaviour can be turned off in about:config (by setting the pref mousewheel.with_alt.action to 1), but I'm wondering if it might make more sense to have it off by default (it could of course still be turned _on_ in about:config).

I would be interested in hearing feedback either way -- whether it's a feature you like and use and think it should remain enabled by default, or whether you also trigger it accidentally and think it would be better off by default.

Thanks!

Re: Should scrolling with the Alt key held down perform history navigation by default?

lackey — Tue, 28 Apr 2026 21:33:59 GMT

I don't think I've ever triggered this accidentally, but now that I know about it, I think I'll try using it!

Re: Should scrolling with the Alt key held down perform history navigation by default?

d9a — Tue, 28 Apr 2026 22:06:33 GMT

I didn't know this existed, but I think I've been bumping into it for a while and chalking it up as a bug.

I use the Alt key as a modifier for moving/resizing windows. Alt+left click to drag a window around without having to grab its titlebar, and alt+right click to resize it based on whichever edge/corner my mouse is closest to, again without having to hit the couple pixel window border. It's hugely convenient -- I can't count the number of times I use it, but it's at least dozens, if not hundreds of times daily.

On rare occasions, Firefox will navigate to a different page right before I start moving a window. I now suspect that's been because I bumped the scroll wheel right before clicking. I just set `mousewheel.with_alt.action` to 0 and added it to my list of about:config changes to make new FF installs more sane, and we'll see how that goes.

So yeah, I'd say this is a pretty weird default. That said, I also think it would be a great setting (visible to users, not buried in about:config) for folks who do want it! It would fit right in with the about:keyboard page people have been begging to have back for over a decade that's still not exposed anywhere. If I didn't have dedicated forward/back buttons on my mouse, I could maybe see myself using this feature on purpose.