1644382 - Page jumps on scrolltop

Status: RESOLVED WORKSFORME

(Web Compatibility :: Site Reports, defect)

Description

[u664636]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:77.0) Gecko/20100101 Firefox/77.0

Steps to reproduce:

Visit: http://smartslider3.com/bugs/firefox/androidscroll/
scroll to the bottom of the page then tap the "Scroll top" button.

Actual results:

The page jumped during the scroll. See video: https://www.youtube.com/watch?v=YAnY8JMSdOo

Expected results:

The page should have scrolled smoothly to the top.

Comment 1

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Moved to GeckoView - if this is a Fenix or A-C bug, please let me know here and I'll move it to GitHub.

Comment 2

[Emily Toop (:fluffyemily)]

snorp thinks that this is a pref that we may have enabled. :botond do you know?

Comment 3

[Kartikaya Gupta (email:[e-mail])]

The page is using jquery's animate function which I believe uses main-thread JS-driven scrolling. With the probably-expensive blur on the page it's not surprising that it's stuttering. It would work better if they used the smooth scroll API which would ask APZ to do the scroll on the compositor. e.g. here is a fixed version: https://mozilla.staktrace.com/bug/1644382_fixed.html

Comment 4

[Botond Ballo [:botond]]

I'm not aware of a recent pref change that would have affected this. Per comment 3, this seems like a page issue, so let's move the bug to Web Compat.

Comment 5

[Oana Arbuzov [:oanaarbuzov]]

Attachment: ScrollSmooth.gif

I'm not able to reproduce the issue, for me the scrolling back to top is smooth.

Tested with:
Browser / Version: Firefox Nightly 201222 (🦎 86.0a1-20201219093321)
Operating System: Samsung Galaxy S8 (Android 9) - 1440 x 2960 pixels, 18.5:9 ratio (~570 ppi density), Huawei P20 Lite (Android 8.0.0) - 1080 x 2280 pixels, 19:9 ratio (~432 ppi density)

Ramona, does it still occur on your side?