I don't see the screensaver activate after the configured idle time.
Confirmed. Broken by http://git.gnome.org/cgit/gnome-session/commit/?id=397cca3a9e5a197860a819a4648bf5bd56969afd Fixed by http://git.gnome.org/cgit/gnome-session/commit/?id=fea641b3be892be65b0c7ef2628268b0998c6408 Will be fixed in the next gnome-session release.
This is indeed fixed.