Created attachment 145744 [details]
Screensharing a whole screen only shows a black screen

SUMMARY
***
Trying to screenshare/screenrecord a whole screen on Wayland only shows a black screen with the cursor inside it. When selecting a single application the window shows fine in the stream, but the cursor isn't shown. xdg-desktop-portal-kde seems to be running according to System monitor.
***


STEPS TO REPRODUCE
1. Open any screenshare/screenrecord application like Firefox, OBS Studio or even the xdg-desktop-portal-kde testing utility (https://invent.kde.org/libraries/xdg-portal-test-kde).
2. Choose to screenshare/screenrecord a whole screen or single window.
3. Select a screen or single window in the xdg-desktop-portal-kde dialog.

OBSERVED RESULT
Black screen with only a cursor when screensharing a whole screen, and the window content when screensharing a single window but whith no cursor. Below are attached some screenshots

EXPECTED RESULT
When selecting a whole screen the whole screen should be seen in the stream (or in the screencapture app like OBS Studio) with the cursor and when selecting a single window that window should be seen in the stream o app with the cursor.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.16.1-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i7-8750H CPU @ 2.20GHz
Memory: 15.5 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 2060/PCIe/SSE2
NVIDIA Driver Version: 495.46

ADDITIONAL INFORMATION
On GNOME scrensharing on Wayland with xdg-desktop-portal-gnome works fine when sharing a whole screen or a single window, with cursor being captured in both cases.