Later X server versions insist on this for some bogus security reason.
dpy=${1?display}; shift
exec xpra --xvfb="Xorg -dpi 75 -noreset -nolisten tcp \
+extension GLX +extension RANDR +extension RENDER \
dpy=${1?display}; shift
exec xpra --xvfb="Xorg -dpi 75 -noreset -nolisten tcp \
+extension GLX +extension RANDR +extension RENDER \
- -config /usr/share/doc/xpra/examples/dummy.xorg.conf \
+ -config xpra-xorg.conf \
-logfile $HOME/.xpra/xserver-$dpy.log" \
"$@" start :$dpy
-logfile $HOME/.xpra/xserver-$dpy.log" \
"$@" start :$dpy