the video hardware driver
those laptop graphics chips treat the VGA connector like a 2nd monitor, I have no idea how you configure linux for multimonitor, but I know its not nearly as easy as MS Windows where it just works.
Indeed that connector is treated as an “all the time on” 2nd monitor
If it is an nvidia card, you can use use the NVIDIA X Server Settings link in “Menu => System => Administration” (if you install the drivers from elrepo, which I recommend)
If it is another card that uses system drivers, you can use the “Menu =>
System => Display”
I just create 2 xorg.conf files and copy the one I need into place when I hook up to my docking station on my Dell M4500.