I have a fresh install of Ubuntu 18.04 and I am using the Mate desktop. On my Razer Blade laptop, when I close the without logging off, then open the lid again, I have to enter my password three times to get back in.
The first unlock screen seems to come from the gnome screensaver, the second and third from mate screensaver. I tried simply killing mate screensaver as an experiment but after waking up from suspend, I get all three lock screens again and mate-screensaver has been restarted somehow.
When I kill gnome-screensaver instead, closing the lid will not suspend my computer any more nor will the screen get locked after a certain timeout.
So there appears to be no simple way to make it work as it should. Is there a way to fix what obviously has got to be an annoying bug?
Is there a bug report about this somewhere, this really should get fixed.
I would probably prefer to have everything handled by gnome-screensaver: not only does it look better, I also use the Ubuntu desktop every now and then and would still want screen locking to work there.