Do you have a set of parent/child processes like this? Note the middle
2 are running on tty63.
ps -f 748 750 926 1089
UID PID PPID C STIME TTY STATTIME CMD
root748 1 0 20:45 ? Ss 0:00 /bin/openvt -c 63 -f -v
-w -- /usr/bin/sudo --user user --login /u
I've gotten Xpra to work with Xdummy on lubuntu 16.04 by by starting
Xpra on a virtual console. This may not support your use case but it
works for mine.
INSTALLATION
sudo apt-get install xpra
apt list xpra
xpra/xenial,now 0.15.8+dfsg-1 amd64 [installed]
sudo usermod -aG tty
USE FROM DE