User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.106 Safari/537.36

Steps to reproduce:

The issue is tested with Firefox Nightly 75.0a1

1. Enable gfx.webrender.all in about:config (gfx.webrender.all = true) and restart the browser
2. Open https://screenster.io/documentation/demo-automation-of-gmail-with-screenster/
3. Start playing video on the page
4. Push the "picture-in-picture" button on the video
5. Move opened window with the video to the second display (the browser window and the video window should be on different displays)

Actual results:

When the window with the video is located on the different display the video in this window starts blinking.
It happens only with gfx.webrender.all = true and when the window with the video is moved to a different display. If it's on the same display, the issue is not reproducible

Expected results:

The video in the "picture-in-picture" mode shouldn't blink

Please reproduce the bug, open about:support, click on "Copy Text to Clipboard" and paste it into https://bugzilla.mozilla.org/attachment.cgi?bugid=1616532&action=enter.

The Firefox Nightly has updated and the issue is not reproducible anymore. So I've reproduced it in Firefox 73.0.1

Yevhen, would you be willing to try to find a regression window for when this was fixed using https://mozilla.github.io/mozregression/

I've found when it was fixed using the "mozregression" tool.
I couldn't find whether it generates any kind of report, so I'm sending you a screenshot.

If you can just copy and paste the bisections information into a bug comment that would be great.

(In reply to Jeff Muizelaar [:jrmuizel] from comment #5)

If you can just copy and paste the bisections information into a bug comment that would be great.

Here is the bisection information:

app_name: firefox
build_date: 2020-02-19 23:56:48.887000
build_file: C:\Users%User%.mozilla\mozregression\persist\311c703cb4e7-shippable--autoland--target.zip
build_type: integration
build_url: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/N0h7vuTGRz63Or_Q5cBKmA/runs/0/artifacts/public%2Fbuild%2Ftarget.zip
changeset: 311c703cb4e7ed220c255f6a3ec41a9cd0781889
pushlog_url: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=0f4fc4e582d369244c46b28ee9f86d0b02dc9e39&tochange=311c703cb4e7ed220c255f6a3ec41a9cd0781889
repo_name: autoland
repo_url: https://hg.mozilla.org/integration/autoland
task_id: N0h7vuTGRz63Or_Q5cBKmA

Yevhen, can you confirm that setting gfx.webrender.compositor = false fixes the problem for you?

(In reply to Jeff Muizelaar [:jrmuizel] from comment #7)

Yevhen, can you confirm that setting gfx.webrender.compositor = false fixes the problem for you?

No, the "gfx.webrender.compositor = false" parameter doesn't fix the problem when "gfx.webrender.all = true"

I've just found that the issue is reproducible only when the Firefox main window is maximized

Ah sorry I was confused.

If you run Nightly and then set gfx.webrender.compositor = false does the problem show up?

Rares, can you see if you can reproduce this in beta?

Hi, I tried to reproduce this issue in our latest Nightly build as well as Beta and Release on a Laptop with Intel UHD 630 and a second Nvidia Geforce GTX 1050 and a second monitor attached via HDMI but I was unable to reproduce it on our end, I only noticed a difference in driver version but I couldnt install it on our laptop cause of some compatibility issues. Our Intel Driver version is 26.20.100.6860 while the user has 26.20.100.7262.

I was unable to reproduce this issue on our end, I tried with WebRender on and off.
I also tried resizing the PIP window, maximized browser window or resizing it to a smaller one.
I've also tried to reproduce this issue on a Desktop PC with 2 monitors and an Nvidia GT 730 but without success.

Bugbug thinks this bug is a regression, but please revert this change in case of error.

NI-ing Kris to see if you can repro at some point

Tried reproducing this with the same intel driver as reporter, but couldn't reproduce. Tried older release matching the user's version, but couldn't reproduce on there either.

@Yevhen: Are you still seeing this on latest versions of Firefox?

(In reply to Kris Taeleman (:ktaeleman) from comment #15)

Tried reproducing this with the same intel driver as reporter, but couldn't reproduce. Tried older release matching the user's version, but couldn't reproduce on there either.

@Yevhen: Are you still seeing this on latest versions of Firefox?

Currently, I don't have access to the 2-display configuration and can't check it. I'll try to check it as soon as possible

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.