1707269 - onscroll listener on div inside of iframe stops receiving events after synchronous ajax request made inside of it

Status: NEW

(Core :: DOM: Events, defect)

Description

[jackthethunder]

Attachment: contains an example which illustrates the bug

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari/537.36

Steps to reproduce:

onscroll listener that is attached to div (residing inside of iframe) stops receiving events after synchronous ajax request was performed inside of it

1. Download and extract ff_bug.zip with with prepared webpage
2. Open index.html with firefox
3. Press ctrl+shift+i to open devtools, activate JS console tab to make JS log visible
4. Scroll grey area
5. Notice "scroll" logs are added or not added to the console depending on ajax enabled or disabled (enabled by default)

• re-assigning current listener to div doesn't help
• assigning new listener to div doesn't help, new listener not firing when performing scroll operations
• manually calling dispatchEvent on div can cause dead listener to act, but only for one call, this doesn't revive dead listener

dead listener can be revived using css: assigning "overflow:clip;" and then back "overflow:scroll;" revives listener, but only until another ajax request

Actual results:

after synchronous ajax request,
scroll listener no longer run when div is scrolled

Expected results:

onscroll event listener must keep receiving subsequent events after synchronous ajax request was made inside of it

Comment 1

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

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

Comment 2

[Negritas Sergiu, Desktop QA]

Hello I have managed to reproduce the issue with Firefox 90.0a1(2021-05-10) 88.0.1 and 89.0b10 on Ubuntu 20, Windows 10 and macOS 10.15. I will set the flags and add this issue to NEW in order to get de developers involved.

Thank you!