1577601 - <iframe> on MDN disappear when switching tab if fission is enabled

Status: RESOLVED FIXED

(Core :: Graphics, defect, P3)

Description

[Danny Colin [:sdk]]

Attachment: firefox-fission-bug.mp4

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

1. Go to an MDN page with an <iframe> (e.g. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/p)
2. Switch to an other tab
3. Go back to the MDN tab

Actual results:

The <iframe> dissapear/stop being rendered (See attached file)

Expected results:

The <iframe> should continue to be rendered

Comment 1

[Simona Badau, Desktop QA]

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0
Build ID: 20190901214807

I can confirm this issue is also reproducible on Windows 10x64-bit on the latest Nightly (when fission.autostart is set to true).
I could not reproduce this issue on Mac OS X 10.14.

Comment 2

[Chris Peterson [:cpeterson]]

Tentatively moving all bugs whose summaries mention "Fission" (or other Fission-related keywords) but are not assigned to a Fission Milestone to the "?" triage milestone.

This will generate a lot of bugmail, so you can filter your bugmail for the following UUID and delete them en masse:

0ee3c76a-bc79-4eb2-8d12-05dc0b68e732

Comment 3

[Hiroyuki Ikezoe (:hiro)]

I believe this was also fixed by bug 1550800. (Though I couldn't reproduce the issue before landing bug 1550800, but I saw the issue on a different MDN page https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API#Thresholds)

Comment 4

[Hiroyuki Ikezoe (:hiro)]

I am going to close this, if someone still has the same issue, please feel free re-open this.