1695914 - "pointerup" event can automatically be triggered on touchscreen devices

Status: RESOLVED INCOMPLETE

(Core :: DOM: Events, defect)

Description

[Toad]

Attachment: pointertest.html

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:86.0) Gecko/20100101 Firefox/86.0

Steps to reproduce:

• Either use a touchscreen device or enable the touch event emulation on desktop.

• On a page that checks pointer events (you can see the attached sample), touch the screen with your finger and lets it on the screen without moving.

Actual results:

After a second or so, the "pointerup" event will be triggered while the finger is still touching the screen.

Expected results:

• The "pointerup" event shouldn't have been triggered in this situation.

• This issue only happens when the pointer type is NOT a mouse.

• Also, this issue doesn't happen when using the touch* events (touchstart / touchend) instead.

• In Chrome, this is working as intended.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::DOM: Events' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Edgar Chen [:edgar]]

I could not reproduce this on Surface Pro on my side.

Comment 3

[Kagami Rosylight [:saschanaz] (they/them)]

Theoretically this can happen when simulating touch input since the InjectTouchInput API expects continuous calls or it timeouts (https://bugzilla.mozilla.org/show_bug.cgi?id=1313170#c5, the behavior still exists although the docs doesn't say that anymore 🤷‍♀️).

But I'm not sure how it can happen with a physical input device. It's also weird if it only happens with pointerup but not touchend. Which device are you using?