Dear Maintainer,

in a multimonitor setup, if I turn my laptop buitin screen off using the Displays panel of Gnome Control Center,
the screen brightness control under Power Savings gets set to 0.
After I turn the builtin screen back on, brightness under Power Savings isn't reset to the value it had before but
remains stuck to 0.

Steps to reproduce:
0) Have a multimonitor setup, with a laptop and an external monitor.
1) Start with 2 monitors on.
2) Turn laptop screen off in Displays (Gnome Controlm Center). Laptop monitor will shut down.
3) (optinally) notice brightness is set to 0 under Power Savings
4) Turn laptop screen back on in Displays.
5) Laptop screen will be black; you now need to readjust brightness (it's working with Fn keys and thru Power Savings for me).

Expected outcome:
Lapton screen has brightness set to a value greater than 0.

Thank you,
regards.