User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:100.0) Gecko/20100101 Firefox/100.0

Steps to reproduce:

Open a video on Windows 11 and switch to fullscreen

Actual results:

It shows a gap between the video and the desktop, Showing wallpaper and icons.
It does not happen on Windows 10, And on google chrome it works just fine.

Expected results:

The video should fill the whole screen

The issue happens on any website.
The only fix that i found is to switch from fullscreen to normal, and switch back to fullscreen.
But if i close firefox and open again the bug happens again.

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

Júlio, could you please attach your about:support output to this report?

It looks like your NVIDIA driver version is pretty current.

You have a lot of extensions active in Firefox. Any chance you could create a fresh profile and try this full-screen behavior using it without all the extensions? I'm curious if there's anything in there that might be interfering.

Sure.
Tried to disabled every extension individually and restarted the firefox and after disabling every single one, the issue persisted.
Created new profile and tested youtube and the issue persisted as well.

Is this all videos?
Does it happen on this video? https://www.youtube.com/watch?v=SORD03t7nlo (I know you said "all websites" but let's make sure we are precisely on the same page)

Yes it happens to all videos / all websites.

Excerpts:

Display0: 1920x1080@165Hz : NVIDIA GeForce RTX 3060 Ti
Display1: 1920x1080@60Hz : NVIDIA GeForce RTX 3060 Ti
DisplayCount: 2
HardwareStretching: both=1 window-only=0 full-screen-only=1 none=0 error=0
GPUProcessPid: 9608
Decision Log
HW_COMPOSITING: available by default
D3D11_COMPOSITING: available by default
DIRECT2D: available by default
D3D11_HW_ANGLE: available by default
GPU_PROCESS: available by default
WEBRENDER: available by default
WEBRENDER_QUALIFIED: available by default
WEBRENDER_COMPOSITOR: available by default

unavailable by runtime: No DirectComposition usage

WEBRENDER_PARTIAL: available by default
WEBRENDER_SHADER_CACHE: available by default
WEBRENDER_OPTIMIZED_SHADERS: available by default
WEBRENDER_ANGLE: available by default
WEBRENDER_DCOMP_PRESENT: available by default

blocked by env: Monitor refresh rate too high/mixed

Monitor refresh rate is 165.
I have two monitors one is 165 of refresh rate other is 60.
But i tested on Windows 10, and it works just fine. Same monitor.

I have a windows 11 AMD machine, and can't reproduce on 100release.
Also, this machine is

HardwareStretching: both=0 window-only=0 full-screen-only=1 none=0 error=0`

And WEBRENDER_DCOMP_PRESENT and WEBRENDER_COMPOSITOR are both available.

It also works for me in nightly102.

Same monitor, Same computer, but on windows 10.

Also i did reinstalled, and the bug still persists.

Glenn, could you please have a look when you get a chance?

I couldn't repro on my local windows machine, but it sounds like it's triggered by some very specific conditions so probably not surprising.

A couple of other pieces of information that would be useful:

• Could you test with just the 60 Hz monitor attached and let us know if it works in that case? (that should allow DC to be enabled in this scenario).

• Do you know what scaling ratio you have set for each monitor in the windows display settings?

Tested on the 60 hz monitor, and the issue stays the same on both monitors.
Scale is 100%

(In reply to Júlio C. Oliveira from comment #16)

Tested on the 60 hz monitor, and the issue stays the same on both monitors.
Scale is 100%

So that had the 165 Hz monitor physically detached? Could you post the contents of your about:support in that case (just so we can confirm that DirectComposition path is being hit in that case).

I tested with only the 165hz monitor connected, the issue is not present.
I tested with only the 60hz monitor connected, the issue is not present.
But if i connect both on my Graphics Card, the issue is present.
Very odd bug.

I don't know if it helps but the 165hz is G-Sync compatible the 60hz monitor is not.

OK, thanks - that confirms that it's only occurring in the non-DC code path. What about if you have both monitors connected and enable gfx.webrender.compositor.force-enabled in about:config (this will require a browser restart). It's possible this might cause other artifacts, but it will be an interesting test to see if it affects the bug above.

With gfx.webrender.compositor.force-enabled set to true the issue persists.

OK, looks like we'll need to try and repro this case locally to understand what is happening. Jeff, Kelsey, do you have anything with a similar set up (a 60 Hz and a 165 Hz monitor on Win11) that you could try repro on?

I don't have a win11 machine for this.

I can confirm that this bug was fixed on the Windows Insider Beta Channel for Windows 11 22H2 (22622.450).
But on Firefox latest (103.0.1) it still persists on Windows 11 stable 21h2 latest (22000.832).

Its a Theme Bug. If i install any custom theme the bug vanishes.
A lot of people are having this same bug for a long time, You can see it on https://www.reddit.com/r/firefox/comments/rhwuvz/firefox_full_screen_on_win11_always_leaves_some/

The bug still persists on Windows 11 22h2 final release 22621.608.
The only fix is a custom theme.
It seems that a new profile the bug does not happen, but as soon as i enable account sync the bug reappears.

The custom theme just fixed temporarily, but the bug returned today. I don't know why. Sometimes it happen sometimes it don't.

The bug still persists on the latest 109.0.1, 9 Months still no bug fix.
There is a lot of people with this issue, can you guys please take a better look at it with Care?
Here is some people with the same issue:
https://www.reddit.com/r/firefox/comments/rhwuvz/firefox_full_screen_on_win11_always_leaves_some/
https://www.reddit.com/r/techsupport/comments/svqg65/fullscreen_bug_gap_in_top_and_left_edge/
https://www.reddit.com/r/FirefoxCSS/comments/t5v70p/what_should_i_do_to_make_this_gap_appear_when/

Here also: https://www.reddit.com/r/firefox/comments/xu5lwy/is_there_a_fix_to_this_full_screen_bug_on_youtube/

Tried Troubleshoot mode and the bug does not happen!, Tried exiting Troubleshoot mode and disable all extensions but didn't managed to fix it.

Found the same issue on firefox support: https://support.mozilla.org/en-US/questions/1363922

This is a duplicate of Bug 1763981.

+1 still not fixed

This is a multi-monitor refresh-rate issue, and we are currently investigating it.

@Bob Hood, I'm sorry but that issue has nothing to do with this issue. Maybe it is caused by the same issue, but definitely not the same issue, my screen don't flicker or glitch or jump around like the videos on that issue. My issue is just a hole on the fullscreen.

(In reply to 08xjcec48 from comment #34)

This is a duplicate of Bug 1763981.

Yes, indeed. Closing as duplicate.