There is a known issue with some apps calling SimulateUserActivity to inhibit screen dimming and this dbus method is only available in gnome-screensaver and not the new gnome-shell lockscreen. That said it should still be possible to disable screen dimming via the lock panel in g-c-c.
Robert and Victor are you using lightdm or gdm?
There is a known issue with some apps calling SimulateUserAct ivity to inhibit screen dimming and this dbus method is only available in gnome-screensaver and not the new gnome-shell lockscreen. That said it should still be possible to disable screen dimming via the lock panel in g-c-c.