1610145 - Touch events can have incorrect clientX/clientY

Status: RESOLVED DUPLICATE of bug 1565512

(GeckoView :: General, defect)

Description

[toasted.nutbread]

Attachment: Video demonstrating the issue

Firefox for Android will sometimes have incorrect values for touch events clientX/clientY when a touch is initiated on an iframe while the visual viewport is zoomed in. The events will also fire on the root document, instead of the events only being sent to the iframe.

I've created an example HTML page + script here: https://github.com/toasted-nutbread/firefox-touch-position-bug. Tapping on the page will show the iframe underneath the "cursor". Touching and moving the page will show a small dot where the touch event is registered.

To reproduce, scroll down the page a little bit, then zoom in. Tap to show the iframe, then try to touch+drag various places inside the iframe. After some attempts, this should eventually result in the dot indicator being updated, but the position will be offset from where the touch is actually occurring.

I have attached a demo video reproducing the issue. Note in the video, the Android touch indicator (white circle) will be offset from the dot indicator (red square). Tested using Firefox for Android Beta 68.5b3.

Comment 1

[Diana Rus]

Hi thank you for the report, reproduced the issue with Nexus 9 (Android 7.1.1) and Samsung Galaxy S9 (Android 9) on Firefox Release 68.4.2, Firefox Beta 68.5b4 and Firefox Nightly 68.5a1 (2020-01-20).

Note:

• The issue can be reproduced on Firefox Preview Nightly 200121 (Build #20210607) GV: 74.0a1-20200115093807
• This also happens on Chrome browser.
  I will put a NI on Chris as this seems a gecko view issue.

Comment 2

[Chris Peterson [:cpeterson]]

(In reply to Diana Rus from comment #1)

• The issue can be reproduced on Firefox Preview Nightly 200121 (Build #20210607) GV: 74.0a1-20200115093807

Thanks for the heads up. Since this bug affects both Fennec and Fenix, I'll move it to the GeckoView Bugzilla component and flag it for the GeckoView team to triage.

• This also happens on Chrome browser.

Though if this bug also happens in Chrome, then this might be an Android bug or a website bug.

Comment 3

[James Willcox (:snorp) ([e-mail]) (he/him)]

Botond, do you think we have a problem here?

Comment 4

[Botond Ballo [:botond]]

I can reproduce this in Fennec, but not in recent GVE or Fenix (and also not in Chrome).

I do think the Fennec behaviour is buggy, but I think the bug has been fixed since the 68esr branch.

Comment 5

[Botond Ballo [:botond]]

The fix range points to bug 1565512. This fix landed on the 70 train and was uplifted to 69, but uplift to 68esr was rejected.

==> This is fixed in Fenix (Firefox Preview), but will not be fixed in Fennec (68esr-based Firefox for Android).