[winswitch] Question: How does Xpra communicate with X11-apps?

[Antoine Martin]

On 09/02/2020 04:09, Olbert, Nils via shifter-users wrote:
> Hello Mr. Martin,
> 
> thanks for your detailed answer.
> 
> One last question: what happens when you set up Xpra to forward a full desktop, like "xpra start-desktop --start-child=fvwm". As X11 only allows one window manager at a time I wonder how this is done - if Xpra acts a compositing window manager and fvwm is launched  two window managers would run simultaneously.
> I guess a nested x server (like Xnest or Xephyr) is used in this case, am I correct?
In desktop mode, xpra does not run as a window manager, it just listens
for paint events on the whole desktop area (the root window):
https://xpra.org/trac/ticket/1247
An earlier version used the approach you describe:
https://xpra.org/trac/ticket/1206

Cheers,
Antoine

> 
> Thanks again,
> 
> Nils