It should just show up in dom0 as another display. In XFCE you can use
Settings | Display to configure it or if you are comfortable with
xrandr you can do it from the console too.
The advantage of the xrandr route is that you can have convenient bash
scripts for different projectors (... different resolutions etc)
In case others would like to know, you can go into the Qubes Applications menu -> System Tools -> Display. Here you can change what shall be shown on the projector and the resolution of the screen.
It seems that the resolution of the PC-screen changes to match the resolution of the projector. And afterwards it is necessary to go into “Display” to change the resolution of the PC-screen back to the resolution that was used before connecting to a projector.
You just plug the HDMI-cable into the computer and the projector will only show the left part of the desktop, which makes it possible to only show windows on the left side of the desktop on the projector while the right side of the desktop-space is used to only show windows on the PC. In case you don’t like this setting, it is possible to change it under “Display” as mentioned above.
And it doesn’t seem to matter if you plug the HDMI-cable into the PC before or after starting the projector and PC or before or after login.
fredag den 13. november 2020 kl. 12.15.33 UTC+1 skrev M: