How to fix: Screen sharing shows black screen with mouse cursor only.

I had an issue which caused me to reinstall my Debian machine. After the reinstall there where two main differences with the previous install:

• Gnome started staggering little bit. The frame rate was low.
• Screen sharing on Gnome in any app didn't work. It shows only black screen with mouse cursor. Chrome, Firefox, Slack - everything was the same.

It happened Gnome was using WayLand by default. A X11 alternative that is meant to perform much better and resolve a lot of issues X11 has. But it doesn't seem to work as flawless as expected, having in mind the two behaviors I listed above.

How to "fix" it.

As the first comment here points out, screen share is broken in WayLand. So to "fix", I moved back to X11. To do so:

1. Log out from Gnome
2. On the login screen use the gear icon to choose Gnome X11.
3. Log in.

After moving back to X11, the frame rate is much smoother and the screen sharing is working again.