Programs with live images just black boxes when shared

I am running Jitsi Meet with Vivaldi Browser (3.6.2165.40) on a Windows 10-64.
It works well with a webcam and audio.
Screen sharing also works, but when selecting ‘Application Window’ I do only see a black box in the selection window for a program which shows live images from a camera with typical 25 fps and it will not be shown on other Windows/Linux PC with Firefox in the meeting.

But when selecting ‘Entire Screen’ it will be shared as part of the screen.
Sharing (nearby) static programs (e.g. Explorer) or the task manager works well.

Is it a Problem with Jitsi or with the browser?
In the bginning I used Firefox on both Linux and Windows, but it showed lower video quality with webcam on Linux, or had problems with the webcam on Windows.

Thanks for hints !!!

Hi and welcome.

This is coming from the browser.

I already had a look at the Vivaldi settings, but did not find a setting which solves the problem, I am using Vivaldi for the first time.
From your experience: Is there a G-free ( preferably FOSS) browser which may be better suited?

Try the latest chromium.

I will give it a try.
I was assuming that the browser behaviour of Vivaldi being a Chromium fork is the the same as of Chromium itself.
Any experience with ungoogled-chromium ?

Thanks !!!

I have tried Chromium 88.0.4324.182 (Developer Build, ungoogled-chromium) (64-bit) on Win 10-64,
but the effect is the same, the program with the live image of a Ethernet camera is shown as a black square in the selection box and it is not shared, the last image of the webcam is shown instead.
But it is shown when sharing the entire screen.
Also tried other programs showing the live image of the camera (not a webcam) and some are shared, others not …

Do you experience the same on getDisplayMedia ?

Yes, it is the same behaviour.

So you can report this to the browsers bug trackers … there is nothing we can do about it, sorry