1917726 - Page unexpectedly shifts when trying to scroll subframe (with toolbar-on-top)

Status: RESOLVED FIXED

(Firefox for Android :: Browser Engine, defect)

Description

[Markus Stange [:mstange]]

Attachment: screen recording

Steps to reproduce:

1. Go to this bus timetable page, or any page which has a vertically-scrollable subframe on a vertically-scrollable page.
2. Scroll down the outer page until you see the subframe / the bus timetable. (This hides the dynamic toolbars.)
3. In the bus timetable, scroll down a little bit, and then scroll up a little bit.

Expected results:
The outer page should remain the way it was, only the subframe should be scrolled.

Actual results:
When scrolling up inside the subframe by just the tiniest amount, the toolbars reappear fully, and cause the entire page to shift down. This is very disorienting.

In the attached screen recording, I was reading the second row of the table, and wanted to scroll back up to the first row ("Westport Railway Station"). But the page shifted so that both row 1 and row 2 are now hidden!

Comment 1

[Petru-Mugurel Lingurar [:petru]]

Think this is assumed but wanted to confirm, this is happening because we get an inputResultDetail which says that the website handled the scroll.

Seems like a good ticket to add to the meta for tracking issues before moving to use scroll data to drive the dynamic toolbar - bug 1915640.
Though now I'm thinking that rather bug 1893221 should be blocking the new meta? That would be so meta! 😏

Comment 2

[BugBot [:suhaib / :marco]]

The severity field is not set for this bug.
:boek, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[BugBot [:suhaib / :marco]]

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

Comment 4

[Markus Stange [:mstange]]

There are two parts to this bug: the page unexpectedly shifting, and the toolbar unexpectedly appearing.
Bug 1921331 is expected to fix the first part. Bug 1914119 is expected to fix the second part.

Comment 5

[Markus Stange [:mstange]]

Attachment: captured page, for posterity

Comment 6

[Alex Jakobi [:ajakobi]]

Attachment: screen recording, slow scroll start does not trigger bug

I've noticed when reproducing the bug (Android emulator on macOS), that gently starting the scroll in the subframe does not trigger the bug.

Comment 7

[Botond Ballo [:botond] [away until Oct 19]]

For reference, https://phabricator.services.mozilla.com/D236774 contains a draft fix for this.

Comment 8

[Alex Jakobi [:ajakobi]]

Attachment: Bug 1917726 - Don't force-expand toolbars during gestures that resemble a scroll up gesture. r=mstange,#android-reviewers

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/8685eaf79f20
https://hg.mozilla.org/integration/autoland/rev/8599d87619b8
Don't force-expand toolbars during gestures that resemble a scroll up gesture. r=mstange,android-reviewers,petru

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/3d47ff163f96
https://hg.mozilla.org/integration/autoland/rev/9dc631489700
Revert "Bug 1917726 - Don't force-expand toolbars during gestures that resemble a scroll up gesture. r=mstange,android-reviewers,petru" for causing build components build bustage at EngineViewScrollingBehaviorTest

Comment 11

[Cristina Horotan [:chorotan]]

Backed out for causing build components bustage at EngineViewScrollingBehaviorTest

Backout link

Push with failures

Failure log

Comment 12

[Alex Jakobi [:ajakobi]]

Will check.

Comment 13

[Phabricator Automation]

Comment on attachment 9517736 [details]
Bug 1917726 - Don't force-expand toolbars during gestures that resemble a scroll up gesture. r=mstange,#android-reviewers

Revision D266354 was moved to bug 1945945. Setting attachment 9517736 [details] to obsolete.

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/d9bfbc144e79
https://hg.mozilla.org/integration/autoland/rev/8bc2e22d7ebb
Don't force-expand toolbars during gestures that resemble a scroll up gesture. r=mstange,android-reviewers,petru

Comment 15

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/8bc2e22d7ebb

Comment 16

[Dianna Smith [:diannaS]]

Confirming I can back this out of 146 beta , leave in 147 nightly and give bug 1999407 more time for a fix?

Comment 17

[Alex Jakobi [:ajakobi]]

Yes, please go ahead an back out. Thanks for your help.

Comment 18

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/93d9e4782ae1
https://hg.mozilla.org/releases/mozilla-beta/rev/01db0bde9c92

Comment 19

[Dianna Smith [:diannaS]]

Backed out for 146.0b7 but stays in 147 waiting on a fix (which will be done in bug 2001536)