1642018 - Rendering bug may render content to wrong tab.

Status: RESOLVED DUPLICATE of bug 1642021

(Firefox :: Security, task)

Description

[tenttipinko]

Noticed this bug after i updated windows to v.2004
I'm on a dual monitor setup. Main is 1080p and secondary is 4k.
I usually have at least 2 firefox windows open. One for each monitor.
If i watch twitch for example in my 4k monitor and surf on my 1080p monitor the surfing tab gets render issues - especially while scrolling.
The security vulnerability comes when it renders parts of the other monitor's tab sometimes.

I don't think it needs to be twitch or some video playing on the other monitor - but it seems to make it worse.

Attached is a obs-captured video showing how twitch from other window gets partly rendered on the other window(on the other monitor)
(only small flashes. but still sensitive information may leak. And it's really annoying in any case)

The url given is the url where i noticed biggest rendering issues. It happens in facebook, reddit etc..

specs:
Windows 64bit v.2004
i7-7700k
gtx-1080ti
16gb ram
ssd