Bug#940047: gdm_shell in remote window will make application windows black

[Dag Nygren]

Package: gnome-shell
Version: 3.30.2-9 (Debian 10)

Starting gnome_shell to a remote X window server will
blacken out any application window displayed in the server.
The same will also happen for any application invoked from
the gnome_shell session

Screenshots attached of the problem attached,

Steps to reproduce:
1. Start remote X-server with TCP access enabled
2. Go to machine running Debian 10 (fully default install)
3. set DISPLAY variable to point to remote server
4. Run xterm
   (screenshot 1)
5. Start gdm_shell and the xterm window will be blacked out
   (screenshot 2)

This problem appeared in an installation using XDMCP and GDM3
protocol remote terminals and worked fine with Debian 9

I traced it down to gnome_shell using a plain Xorg server
just to simplify debugging the problem

Best Regards

-- 
Dag Nygren                               email: dag at newtech.fi
Oy Espoon NewTech Ab                     phone: +358 9 8024910
Träsktorpet 3                           Mobile: +358 400 426312
02360 ESBO
FINLAND
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