1697769 - User is unable to scroll using the scroll bar inside the Hamburger menu on Touch devices

Status: RESOLVED FIXED

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Rares Doghi, Desktop QA]

[Affected versions]
Nightly 88

[Affected platforms]
Touch devices

[Steps to reproduce]

1. Launch the Firefox browser and open the Hamburger menu.
2. Try to move the scroll bar inside the Hamburger menu.

[Expected result]
The User should be able to scroll inside the Hamburger menu using the scroll bar on touch devices.

[Actual result]
The scroll bar remains fixed and the user is unable to scroll inside the hamburger menu using it.

Push Log from the first Bad build
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=fddc94978eb7f42cca5d199b94164d133facc3e7&tochange=31462a8e07406103e8d97b19faf9af3bd63530b6
It seems that Bug 1682527 might cause this issue.

Comment 1

[Rares Doghi, Desktop QA]

Edgar do you mind taking a look at this issue ?

Comment 2

[Edgar Chen [:edgar] (Parental leave until Oct. 09.)]

Attachment: Bug 1697769 - Apply implicit pointer capture only for pointer events that are generated from the touch events;

Comment 3

[Edgar Chen [:edgar] (Parental leave until Oct. 09.)]

Okay, after some investigation, dragging scrollbar doesn't work because nsSliderFrame::HandleEvent isn't run.

In Windows, the touch action on chrome popup would generate compatibility mouse events instead, see https://searchfox.org/mozilla-central/rev/fa48ebee58d59fa846919c3e2c3122b08db57c9c/widget/windows/nsWindow.cpp#8129-8135. And when implicitly pointer capture is enabled, we run the HandleEvent of the captured element's primary frame, i.e. thumb's frame, instead of the scrollbar's frame.

I wrote a test to simulate the issue, touch event doesn't have the same issue because we take the captureContent in PresShell into account in https://searchfox.org/mozilla-central/rev/fa48ebee58d59fa846919c3e2c3122b08db57c9c/layout/base/PresShell.cpp#8712-8719, the capture content is set in https://searchfox.org/mozilla-central/rev/fa48ebee58d59fa846919c3e2c3122b08db57c9c/layout/xul/nsSliderFrame.cpp#1277-1286.

Comment 4

[Edgar Chen [:edgar] (Parental leave until Oct. 09.)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ab751fc3cdd6551cd25f3d0d6e56321ca0d1b98c

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d3ff81521b17
Apply implicit pointer capture only for pointer events that are generated from the touch events; r=smaug

Comment 6

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/d3ff81521b17