Comment 10 for bug 1521000

Hi! This bug (re)appeared in my freshest Xubuntu! Just upgraded to xenial.
I have "xfce4-settings 4.12.0-2ubuntu1 amd64" (if it matters).

I have 2 displays, one is the laptop's native LVDS1 monitor and other is a HDMI1 monitor (Samsung SyncMaster P2450).
In Settings/Display I configured that only the "Samsung" to be used, i.e. the "Laptop" be disabled. My settings were accepted, everything worked fine.

(Instead of Light Locker, which seems to be buggy, I use gnome-screensaver.)

When I minimize the windows (Super+d), bring up the "Log Out" dialog (Alt+F4) and choose Suspend, the system goes to suspend, okay. When resuming, instead of the HDMI, the LVDS display turns on. Asks for password, and resumes my session - on the laptops's display, instead of the hdmi.
When I go to the Settings/Display, I can see that "somebody" enabled the laptop display and disabled the hdmi.
When I click on the "use this display" below the samsung, the samsung display remains black (off)!
When I click on the same checkbox secondly, then the samsung display switches ON! (In each case, a dialog appears to keep or not this configuration.)