Every time I have to connect to an external monitor, it remains "disconnected" according to xrandr and the second screen remains black.
To solve this problem, I always have to close all my GUI apps and the X server, login again and restart everything.
Tests I did : if I go to tty2 before doing this, the screen is duplicated as expected but when I go back to tty1 (which I use to startx) it disappears.
My config is Arch Linux + bspwm, my .xinitrc is simply exec bspwm
I'd really like to keep my programs open whenever I need to do a presentation.