Ensure that the lightbox is above everything (including the screenlock
itself) when fading in - this allows for fading while showing the
unlock dialog. Also, don't pushModal again when already locked, or
we won't get out of it.
https://bugzilla.gnome.org/show_bug.cgi?id=619955
When the screenshield is deactivated, instead of going back to the
session immediately, prompt the user for authentication.
This essentially reinstates what used to be provided by gnome-screensaver.
https://bugzilla.gnome.org/show_bug.cgi?id=619955
We are replacing the gnome-screensaver module with with a screen shield
that is part of gnome-shell.
This patch fades out the screen on idle and shows a shield with a background
image when there is activity again. The shield can be removed with a key or
button press.
https://bugzilla.gnome.org/show_bug.cgi?id=619955
