Closed Bug 1687507 Opened 4 years ago Closed 4 years ago

Smooth scrolling is broken on some pages

Categories

(Core :: Panning and Zooming, defect)

Product:
Core
Component:
Panning and Zooming
Version:
Firefox 84
Type:
defect

Tracking

()

Status:
RESOLVED DUPLICATE of bug 1684520

People

(Reporter: vladimir.didenko, Unassigned)

Details

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36

Steps to reproduce:

Smooth scrolling is not working on some pages or it could be broken when some pages are opened in the new tab.

E.g. this bug could be easily reproduced on the site https://www.linux.org.ru using the following steps:

  1. Go to the main page https://www.linux.org.ru
  2. Scroll page using a keyboard (arrow up/down). Smooth scrolling is working as expected.
  3. Open in new tab page from this site e.g.
    https://www.linux.org.ru/news/opensource/16117183
  4. Try scrolling on the main page (https://www.linux.org.ru) or on the opened page.

Actual results:

Scrolling becomes jumpy/not smooth. Even if you close an additional page and leave the main page opened smooth scrolling will stay broken until Firefox restart.

I was able to reproduce this issue both on Windows and Linux and on two different machines. One machine has Radeon 5700 XT GPU and another one is a laptop with Intel 1065G7.

Note that this issue didn't exist for me on Firefox 81. I also tested it on Firefox Nightly and it still persists.

Expected results:

Smooth scrolling should work

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Component: Untriaged → Panning and Zooming
Product: Firefox → Core

Could you run mozregression https://mozilla.github.io/mozregression/ to narrow down to a specific change that caused this to happen? Thanks

Flags: needinfo?(vladimir.didenko)

Just in case if it is relevant. In all setups, I am using a 4K screen.(In reply to Timothy Nikkel (:tnikkel) from comment #2)

Could you run mozregression https://mozilla.github.io/mozregression/ to narrow down to a specific change that caused this to happen? Thanks

Sure. Below is the output of mozregression:

2021-01-20T14:58:21.717000: DEBUG : Found commit message:
Bug 1657822. Enable new desktop zooming scrollbar code. r=kats

The mathml reftest pref needs to be added at the same time because the test needs that pref with the new scrollbar code to pass, but it fails with that pref with the old scrollbar code. Since that test uses the minimum scale, which is only valid with overlay scrollbars, it is correct to do so.

Differential Revision: https://phabricator.services.mozilla.com/D91243
Flags: needinfo?(vladimir.didenko)

Based on the similar symptoms and same regressing bug, I think this is a duplicate of bug 1684520.

Status: UNCONFIRMED → RESOLVED
Closed: 4 years ago
Resolution: --- → DUPLICATE
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