1663646 - [touchpad] Pinch zooming on dropdowns scrolls through the dropdown

Status: NEW

(Core :: Panning and Zooming, defect, P3)

Description

[Hani Yacoub, Desktop QA]

Affected versions

Firefox Nightly 82.0a1

Affected platforms

Windows 10 x64

Preconditions

fx.webrender.all = true OR fx.webrender.all = false
apz.allow_zooming = true
apz.windows.use_direct_manipulation = true

Steps to reproduce

1. Navigate to a page which contains dropdown lists (e.g.https://twitter.com/i/flow/signup).
2. Open a dropdown list(e.g. Day).
3. Pinch zoom in using a touchpad on the dropdown.

Expected result

Pinch zooming on dropdowns should be totally ignored.

Actual Result

Pinch zooming on dropdowns scrolls through the dropdown.

Suggested severity

S3

Comment 1

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

I suspect this needs to be fixed in APZ - we're probably using the "two finger pinch also allows scrolling" code and maybe we should make that conditional on certain types of input devices and/or platforms. In particular if the input source (touchpad in this case) already has heuristics to select panning vs zooming then we should probably not allow the zooming code to allow plain panning, or something along those lines.

That being said I'm not sure if this worth blocking release, it could be post-release item.

Comment 2

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

bug 1648641 needs more work when I thought it was done, so unassigning this until I'm done dealing with that.

Comment 3

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

So actually this happens regardless of apz.allow_zooming and even happens if I force-disable direct manipulation. It also happens in current Firefox release on Windows. I also ran with logging enabled and it doesn't look like it's hitting any of the APZ codepaths at all.

Can you confirm you see the same behaviour on current the release version?

Comment 4

[Hani Yacoub, Desktop QA]

Yes, I confirm that i see the same behaviour on current release version.

Comment 5

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

Thanks. In that case this is not specific to desktop zoom and doesn't need to block.