User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

Open about firefox section and move the cursor between top of the full window and center. It dissapears by disabling the hardware acceleration from firefox settings.

Actual results:

Anytime i open about firefox section, seeing a shadow glitch which is in the attach. This issue also happens and visible if i open right click menu on new tab section and do the same moves.

Expected results:

No shadow glitch.

Hi,
I didn't manage to reproduce this issue on my machine(win 10) with Firefox Release 70.0.1.
Please test if the issue also occurs in safe mode. Here is a link that can help you with that:
https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
If the issue still persists, please test it using a new profile, you can find the steps to do that below:
https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles?redirectlocale=en-US&redirectslug=Managing-profiles#w_starting-the-profile-manager

Interestingly, it doesn't occur in safe mode with hardware accelaration enabled. Just because this, i removed firefox and delete profiles from appdata folder and installed again. I also installed latest video driver. It's still happening in normal use. I disabled all extensions and delete all themes manually in normal mode. No change.

Since this issue doesn't occur in safe mode with hardware acceleration enabled, this might be related to some extensions that are not visible but are enabled by default on firefox install(normal mode). Can a dev,please, take a look over this bug?

Thank you!

I figured out something. I installed Firefox 69.0 version and and it works normal, no glitch. I realized that with 70.0 version webrender compositor enabled by default and that's the point. In about:support compositing section, Firefox 69 says direct3d11(advanced layers), Firefox 71 says WebRender. I guess there's something wrong with WebRender feature.

(In reply to unahombre1 from comment #4)

I figured out something. I installed Firefox 69.0 version and and it works normal, no glitch. I realized that with 70.0 version webrender compositor enabled by default and that's the point. In about:support compositing section, Firefox 69 says direct3d11(advanced layers), Firefox 71 says WebRender. I guess there's something wrong with WebRender feature.

If i disable webrender from about:config in 71.0 it's working fine. I realized another thing. When webrender is disable, there's no white flashes when firefox is closing.

So two things happens when WebRender enable. This shadow glitch and white flash when close Firefox. This is a WebRender bug.

I confirmed the same bug.
This bug does not occur when gfx.webrender.dcomp-win.enabled;false.

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0
Intel Iris Plus Graphics 655 (26.20.100.7529)

I tried to reproduce this on nightly with an Intel HD530 and NVIDIA GTX 1050, but I couldn't see any artifacts. I might be looking at the wrong thing, or maybe it's device specific, or maybe it's fixed on nightly?

Is anyone else able to reliably reproduce it on nightly?

I tried 73.0 nightly. It's still occurs.

(In reply to unahombre1 from comment #8)

I tried 73.0 nightly. It's still occurs.

I tried it 2 days ago. It was there. i tried again. Now glitch is fixed, thanks. But white flash on closing still there. When i disable webrender there's no white flash on closing.

unahombre1, can you upload about:support information? Thanks.

From the symptom in comment 0, it seems like a driver problem.

I didn't change the driver. I guess glitch has fixed by devs. But as i said white flash on closing still occurs. Attached the support information.

(In reply to unahombre1 from comment #9)

I tried it 2 days ago. It was there. i tried again. Now glitch is fixed, thanks. But white flash on closing still there. When i disable webrender there's no white flash on closing.

From the timing, the glitch might be addressed by Bug 1592509 .

(In reply to unahombre1 from comment #13)

I didn't change the driver. I guess glitch has fixed by devs. But as i said white flash on closing still occurs. Attached the support information.

unahombre1, can you take a video of the white flash? Thanks.

While gfx.webrender.force-disabled;true and browser.startup.blankWindow;false

shorter but still a little flash when opening, no flash when closing.

(In reply to Sotaro Ikeda [:sotaro away Dec/28 - Jan/5] from comment #14)

(In reply to unahombre1 from comment #9)

I tried it 2 days ago. It was there. i tried again. Now glitch is fixed, thanks. But white flash on closing still there. When i disable webrender there's no white flash on closing.

From the timing, the glitch might be addressed by Bug 1592509 .

The glitch is back again on latest nightly.

When gfx.webrender.force-disabled;true glitch and white flash on closing disappears.

(In reply to unahombre1 from comment #20)

When gfx.webrender.force-disabled;true glitch and white flash on closing disappears.

and also https://bugzilla.mozilla.org/show_bug.cgi?id=1601204 this bug dissapears.

This bug is bit confusing to follow. Is it possible for you to file new separate issues for each part if you're still seeing them?

1. Shadow glitch in the first attached video, and dai's video still appears on latest nightly. It dissapears when "gfx.webrender.force-disabled;true".

2. There's a white flash on opening. It doesn't related with webrender. It's happening always. Video: https://bugzilla.mozilla.org/attachment.cgi?id=9115149

3.There's a white flash on closing. It dissapears when "gfx.webrender.force-disabled;true"

4. I have the same bug in here: https://bugzilla.mozilla.org/show_bug.cgi?id=1601204
   and it dissapears when "gfx.webrender.force-disabled;true".

Sorry,

*3. It dissapears when "gfx.webrender.dcomp-win.enabled;false"

*4. It dissapears when "gfx.webrender.dcomp-win.enabled;false"

https://downloadcenter.intel.com/download/29335/Intel-Graphics-Windows-10-DCH-Drivers

Can you try updating to Intel 26.20.100.7755 driver and see if it helps?

(In reply to GMA from comment #25)

https://downloadcenter.intel.com/download/29335/Intel-Graphics-Windows-10-DCH-Drivers

Can you try updating to Intel 26.20.100.7755 driver and see if it helps?

I updated yesterday. Still occurs on 72.0.2.

Still occurs on 74.0

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

Reverting summary change. White flash is bug 1566685. In comment 6, window shadow seems to flicker softly when hovering the window.

It looks like this flicker bug has solved with 75.0 version in default settings. White flash on opening and closing still exists.