User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.198 Safari/537.36

Steps to reproduce:

https://drive.google.com/file/d/1YKo21vkIreWSJRv3v91zi1esJ51ehNA2/view?usp=sharing

1. Visit or refresh at url: https://app.clubhouse.io/demoorg/story/85/pull-together-feedback-on-frustrations-with-onboarding#activity-249
2. wait 1 second until content scrolls to the activity location
3. hover over the center of the dialog
4. use mouse wheel to scroll up and down
5. observe flickering content at the top of the dialog
6. grab dialog scrollbar and drag beyond upper limit
7. observe content at the bottom of the dialog slowly disappears

Actual results:

5. observe flickering content at the top of the dialog
6. observe content at the bottom of the dialog slowly disappears

Expected results:

5. no flickering content at the top of the dialog
6. content at the bottom of the dialog does not slowly disappears

I'm a developer for Clubhouse (https://clubhouse.io/), and our team has received multiple complaints with similar issues as described in this bug. It seems like many of them report the issue on Firefox 82, but some experienced similar issues before Firefox 82 was officially released. All of the reports are from Linux or OSX users. The issues describe above do not exist in Chrome.

The steps to reproduce were executed using OSX 10.15.7 and Firefox 82 on a machine with the following system specs:

MacBook Pro (15-inch, 2018)
Radeon Pro 555X 4 GB
Intel UHD Graphics 630 1536 MB

I can't access the url (even after creating a test account). Is there a way that you can share the page that causes the issue with us? If you need you can share a test account login information or url privately.

Alternatively, you could try running https://mozilla.github.io/mozregression/ to determine what change caused this? You would want to make sure to set the pref gfx.webrender.force-disabled to true to ensure that webrender stays disabled so you can reproduce the bug.

@tnikkel Thanks for trying to access the url, sorry that it doesn't work even after creating an account. (I assumed that it would.) I'll investigate and get back to you soon.

@tnikkel: You should have access now, sorry for the trouble.

Thanks. I was able to reproduce. It turns out that we've fixed this already in bug 1674935. That fix will be included in Firefox 83 which comes out Nov 16.

You can verify that the problem is fixed for you by downloading Firefox Beta or Nightly.

I'm going to mark this bug as duplicate of the bug that fixed it. If there is anything else, let me know.

Thanks so much for the quick response @tnikkel! It's great to hear that the bug has been fixed and will be released soon.