move windows from one computer display to another

#move windows from one computer to another

####on computer 1####
#install xpra -- zenity is just for example
sudo apt install xpra zenity

#start xpra - '20' is an unused display
xpra start :20

#start a program on that display
export DISPLAY=:20
zenity --info --text 'Msg Box 1' &

#or start it with a program
xpra start :20 --start='zenity --info --text "this is a test"'

#zenity is now running on display 20
#to view that display, attach to it
#giving the display number is only needed if there is more than one xpra server runnning
#but I put it in anyway, just to be sure
xpra attach :20

#######On Computer 2#########
#now, login from remote machine
ssh -X <user>@<computer 1>

#move programs to comptuer 2
xpra attach :20