I am having the same problem when using stumpwm on arch-linux
I have eDP (laptop) and monitor (HDMI-A-0). I prefer having the monitor to left-of laptop, and things were working fine until yesterday when I connected a projector and somehow things got messed up and I'm unable to recover now. Now, when I login to stumpwm, the default mode is monitor to right-of laptop, and things work fine. But when I move the monitor to left-of laptop,
xrandr shows correct values set. even the background image takes the full screen
however, the windows only take up partial screen on monitor. and the windows on the laptop overflow onto the monitor
I've tried, arandr, but get the same results