1786658 - Uncontrolled jumpy scrolling in websites with "infinite scroll" interface or very long pages.

Status: RESOLVED WORKSFORME

(Core :: Panning and Zooming, defect, P2)

Description

[Peter da Silva]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:103.0) Gecko/20100101 Firefox/103.0

Steps to reproduce:

Visit Facebook, Twitter, Reddit, or other site with very long webpages particularly the ones with an "infinite scroll" interface to their feed.

Scroll down in the feed for a few minutes.

Actual results:

The feed starts jumping back and forth several items, or scrolls down significantly and won't reliably scroll back to where you were.

This has happened on multiple sites, on two computers (Mac mini Desktop and Macbook Pro).

I may have been able to mitigate it on Facebook by closing the contacts pane which has its own scrollbar, but I could just have been imagining it.

Expected results:

Scrolling smoothly and regularly like it used to.

I don't know if multiple social media sites have simultaneously broken scrolling, but I suspect it's something in recent Firefox on Mac.

My original report has been turned into a Facebook-specific bug. This is not a facebook-specific problem. As requested I am opening a new bug.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Panning and Zooming' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Hiroyuki Ikezoe (:hiro)]

Hey Peter, if you think it's a recent regression in Firefox. Please give us feedback when it got regressed by using https://mozilla.github.io/mozregression/ ? It would be a great step to forward this issue. Thanks!

Comment 3

[Hiroyuki Ikezoe (:hiro)]

I mean not the case on Facebook.

Comment 4

[heart_of_greed]

I have the same issue, for facebook it jumps like crazy. For reddit, after scrolling down it jumps back one scroll. I noticed this issue since around FF 100-101 (at least that's when I started using FF)

Comment 5

[Peter da Silva]

I don't know how recent it is, or whether it was a change in Firefox or how sites implement infinite scroll.

Another site it shows up in is virtualverse.one, which isn't infinite scroll but at 50 posts per page they can get long enough to start jumping.

Comment 6

[Hiroyuki Ikezoe (:hiro)]

If this jumpy scrolling is caused by the same root cause of bug 1779404, and if we considered this bug is a regression, then bug 1561450 is a regressor. It was 3 years ago. I don't think it's recent. I am mostly 100% sure this bug was triggered by (a) change(s) in each site.

(In reply to Peter da Silva from comment #5)

Another site it shows up in is virtualverse.one, which isn't infinite scroll but at 50 posts per page they can get long enough to start jumping.

I am sure this kind of jumpy scrolling is not relevant with infinite scroll interface, the issue can happen in normal scrolling contents. Though it more often happens in cases of infinite scrolling.

Comment 7

[Bogdan Maris, Desktop Test Engineering]

Using Latest Nightly 107.0a1 from today on macOS 11.6 I can't reproduce this issue on multiple websites with long scrolls (virtualverse.one, treeherder) or infinite scrolls (reddit.com, 9gag.com).

Could you attach the info from about:support webpage here?
Could you try and use a new profile and see if you this is still reproducible for you? https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Comment 8

[Hiroyuki Ikezoe (:hiro)]

Peter, I just want to clarify whether the unexpected jumps still happen on the latest release version of Firefox (115). Are you still seeing it?

Comment 9

[Peter da Silva]

I just this minute updated, and it does seem to be better but I just restarted (because update) so that may not be useful information yet...

OK, on Facebook in no longer seems to be jumping back and forth a few pages, but after scrolling down a while I get random jumps back to the top of the scroll and lose my place, and have to start again. The distance scrolled before the jump is not consistent and seems to get longer each time, but the scroll-bar has shrunk to less than 5% at the time it happens.

I will monitor and get back to you.

Comment 10

[Peter da Silva]

That could just be Zuck being a jerk.

Comment 11

[Peter da Silva]

Facebook just started doing it again.

Comment 12

[Botond Ballo [:botond]]

Hi Peter -- since the original report mentions the issue happening on other website with an infinite scroll interface such as Twitter or Reddit, I would also be curious to know whether you have experienced the issue in recent Firefox versions (>= 115) on sites other than Facebook

Comment 13

[Peter da Silva]

Sorry, yes, it has continued being a problem on all the mentioned sites. The apparent improvement after I updated seems to have been an artifact of restarting Firefox to update.

Comment 14

[Peter da Silva]

One thing to note, turning the scroll wheel v e r y slowly avoids the problem.

Comment 15

[Botond Ballo [:botond]]

Hi Peter, I wanted to check in with you to see whether this is still something you experience. We made a variety of fixes to the relevant code areas over time (bug 1833758, bug 1852818, bug 1779404, bug 1856088, bug 1871760) which may have fixed or improved this.

If it still happens, and you're interested in performing some additional diagnostic steps to try to get to the bottom of it, we have some ideas for what to try.

Comment 16

[Peter da Silva]

You know I haven't had a problem with this in a while. I think you've scotched that serpent. Bravo!

Comment 17

[Botond Ballo [:botond]]

That's wonderful to hear! I'll close this now; please feel free to reopen if this happens again.