User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0
Steps to reproduce:
This bug can be observed in effect on https://projectvinyl.net/ . I have a fix yet that has not yet been deployed, so if you cannot reproduce go to Inspect and remove the "no-3d" class from the top of the document.
- Scroll down part way on the page (only needs to be by a little, the bug only appears when scrollY > 0 on the element where perspective and perspective-origin have been set)
- Attempt to click and drag the horizontal scrollbar on any of the video carousels.
- Attempt to click and drag the vertical scrollbar on the twitter iframe
In the case of the horizontal scrollbars:
The scrollbar will either not move at all, or snap suddenly to the opposite as soon as you click.
In the case of the vertical scrollbar:
The scroll position will snap to an offset from the mouse position proportional to the distance the main page has been scrolled.
Both scrollbars should move smoothly with the cursor with no offset (as scrollbars are want to do)
I have not been able to reproduce this bug on Chrome.
It is not present in Nightly versions - instead the 3d transform has a pronounced jittery effect (82.0a1 (2020-08-31) (64-bit))
This issue was observed previously in prior versions of production Firefox (as late as 2019), and I have not noticed the issue again until very recently (80.0 (64-bit))
I'd previously filed a bug report for an issue similar to this, that I was unable to find, and which I assumed would have been resolved by the release of Firefox 80 as I've been using Nightly for several months now (since 79) with no issue.