1947470 - hdfcbank.com - When typing in the support chat, it gets scrolled to the top

Status: VERIFIED FIXED

(Core :: Panning and Zooming, defect, P1)

Description

[Calin Tanase]

Attachment: Nightly vs Chrome vs Release.mp4

Environment:
Operating system: OnePlus 6 A6000 (Android 11)
Firefox version: Nightly 137.0a1-20250209212051, Beta 136.0-20250207091649, Release 135.0-20250130195129

Preconditions:
• Clean profile

Steps to reproduce:

1. Go to https://www.hdfcbank.com
2. Tap on "ASK EVA" button located at the bottom of the screen close to the center.
3. Tap on the message box.
4. Scroll up to make the message box visible again.
5. Type something.

Expected Behavior:
The chat remains on the same position.

Actual Behavior:
The chat gets scrolled to the top, hiding the message box.

Notes:

1. Screen rec attached
2. There are 2 layouts for the chat, doesn't seem to affect this behavior
3. Reproducible regardless of the ETP status
4. Not reproducible on Firefox Release and Chrome
5. Issue found during WebCompat team [Top100] websites testing

Comment 1

[Emilio Cobos Álvarez [:emilio]]

So I can reproduce once the chat is long enough. It seems we're scrolling the input into view, but it is covered by the dynamic toolbar. Hiro, you've recently looked at similar issues, can you take a look?

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Botond suggests that bug 1949319 is unlikely to be the cause of this.

Comment 3

[Hiroyuki Ikezoe (:hiro)]

Attachment: A reduced test case

Comment 4

[Hiroyuki Ikezoe (:hiro)]

Attachment: Bug 1947470 - Rename helper_zoomToFocusedInput_scroll_visually.html and add another variant of the mochitest. r?dlrobertson

As of this commit the new mochitest fails, it will suceed after the next
change.

Comment 5

[Hiroyuki Ikezoe (:hiro)]

Attachment: Bug 1947470 - Offset the target position:fixed element by the layout scroll offset. r?dlrobertson

Comment 6

[Hiroyuki Ikezoe (:hiro)]

Attachment: Bug 1947470 - Rename visual-scrollIntoView.html and add another variant of the test. r?dlrobertson

A big difference of the new test is that it's testing on the root scroll
container which has been already scrolled to some extent.

Just like the original test, this new test doesn't work on Firefox
because of the lack of the support of touch actions.

Comment 7

[Daniel Holbert [:dholbert]]

(moving this to diagnosis-team:apz to reflect reality, since hiro's looking into this. Thanks, hiro!)

Comment 8

[Botond Ballo [:botond]]

Removing needs-diagnosis flag since we have a diagnosis (and a proposed fix).

Comment 9

[Hiroyuki Ikezoe (:hiro)]

I am going to land only D239480 and D239482 since I'd like to fix bug 1950744 case in D239481 altogether.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/79a9ca542d3e
Rename visual-scrollIntoView.html and add another variant of the test. r=dlrobertson
https://hg.mozilla.org/integration/autoland/rev/583a00c3f77d
Rename helper_zoomToFocusedInput_scroll_visually.html and add another variant of the mochitest. r=dlrobertson

Comment 11

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/51416 for changes under testing/web-platform/tests

Comment 12

[Sandor Molnar[:smolnar]]

Backed out for causing mochitest failures @ test_group_zoomToFocusedInput

Backout link: https://hg.mozilla.org/integration/autoland/rev/5389dad673aca26f9acf7df4d96e05f1ca1fae4a

Push with failures

Failure log -> TEST-UNEXPECTED-PASS | gfx/layers/apz/test/mochitest/test_group_zoomToFocusedInput.html | helper_zoomToFocusedInput_scroll_visually_bug1947470.html

Comment 13

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR was closed without merging

Comment 14

[Hiroyuki Ikezoe (:hiro)]

(In reply to Sandor Molnar[:smolnar] from comment #12)

Backed out for causing mochitest failures @ test_group_zoomToFocusedInput

Backout link: https://hg.mozilla.org/integration/autoland/rev/5389dad673aca26f9acf7df4d96e05f1ca1fae4a

Push with failures

Failure log -> TEST-UNEXPECTED-PASS | gfx/layers/apz/test/mochitest/test_group_zoomToFocusedInput.html | helper_zoomToFocusedInput_scroll_visually_bug1947470.html

On our Android environments, scrollTo(0, 1000) isn't sufficient to hit this bug's condition. (The window.innerHeight value was 1136px).

I changed it to scrollTo(0, 2000).

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/952cbe94a2c0
Rename visual-scrollIntoView.html and add another variant of the test. r=dlrobertson
https://hg.mozilla.org/integration/autoland/rev/1c4f95d4f25e
Rename helper_zoomToFocusedInput_scroll_visually.html and add another variant of the mochitest. r=dlrobertson

Comment 16

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/952cbe94a2c0
https://hg.mozilla.org/mozilla-central/rev/1c4f95d4f25e

Comment 17

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 18

[Hiroyuki Ikezoe (:hiro)]

Attachment: Bug 1947470 - Add another variant test case. r?botond,dlrobertson

This case is similar to helper_scrollIntoView_bug1950744.html [1], a big
difference is that the position:fixed element is in view, but some part of
the element is overflowed from the layout viewport. Thus we fail to check [2]
whether the given position:fixed element is inside the visual viewport.

[1] https://searchfox.org/mozilla-central/rev/5fb48bf50516ed2529d533e5dfe49b4752efb8b8/gfx/layers/apz/test/mochitest/helper_scrollIntoView_bug1950744.html
[2] https://searchfox.org/mozilla-central/rev/7857ea04d142f2abc0d777085f9e54526c7cedf9/layout/base/PresShell.cpp#3847-3854

Comment 19

[Hiroyuki Ikezoe (:hiro)]

Attachment: Bug 1947470 - Do MoveInsideAndClamp for the given position:fixed rectangle to avoid unexpected scrolling. r?botond,dlrobertson

For safety, both of helper_scrollIntoView_bug1950744.html and
helper_scrollIntoView_bug1950744-2.html run with
layout.scroll_fixed_content_into_view_visually=true and
layout.scroll_fixed_content_into_view_visually=false because these tests
should NOT cause any scrolling regardless of the pref value.

Comment 20

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/37668aab8da6
Add another variant test case. r=dlrobertson
https://hg.mozilla.org/integration/autoland/rev/17ae8bd538ed
Do MoveInsideAndClamp for the given position:fixed rectangle to avoid unexpected scrolling. r=dlrobertson
https://hg.mozilla.org/integration/autoland/rev/1959c3b0822f
Offset the target position:fixed element by the layout scroll offset. r=dlrobertson

Comment 21

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/37668aab8da6
https://hg.mozilla.org/mozilla-central/rev/17ae8bd538ed
https://hg.mozilla.org/mozilla-central/rev/1959c3b0822f

Comment 22

[Hiroyuki Ikezoe (:hiro)]

Comment on attachment 9468212 [details]
Bug 1947470 - Offset the target position:fixed element by the layout scroll offset. r?dlrobertson

Beta/Release Uplift Approval Request

• User impact if declined/Reason for urgency: A bank site is totally unusable, also sites such as bug 1950744 case keep broken
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: none
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): We've already haven a mitigation that this code change doesn't affect on desktop at all (bug 1955158)
• String changes made/needed: none
• Is Android affected?: Yes

Comment 23

[Dianna Smith [:diannaS]]

Comment on attachment 9468212 [details]
Bug 1947470 - Offset the target position:fixed element by the layout scroll offset. r?dlrobertson

Approved for 138.0b6

Comment 24

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/8f4b1f6504ae

Comment 25

[Vasilica Tamas (Android QA) [:vtamas]]

Attachment: chatissue.mp4

This issue is verified as fixed on Firefox for Android Nightly 139 (2025-04-13) and Firefox 138 Beta beta 6 under OnePlus 6T (Android 11) and Samsung S24 Ultra (Android 14). Confirming that the chat remains visible during the entire typing process.