I boot my laptop to linux, with the lid closed and with an external display on the HDMI port. The system now decided to set up the monitors with extended displays, even though the lid is closed. I can only access the right display, and can't find a way to disable the internal (left) display. I can launch the display settings, but it only shows on the left display. On Windows theres some trickery to drag an application that's not visible by using the keyboard, but I don't find it for XFCE4.
xfce4-display-settings allows a --display flag, but I believe an extended display is only accessible as :0.0.
I see you can install a program or a script to solve it, but was wondering if there's a more convenient way to deal with this... either to disable the extended display, or launch xfce4-display-settings on a certain screen.