I'm no longer able to bring up the "unlock" dialog after the screen is locked and monitor turned off.

Steps to produce the problem:

1. In Gnome, press <Super>l or click the menu entry to lock screen.
2. Do nothing until the screen turns blank (very soon).
3. Hit <Space> or any key on keyboard, or move the mouse. This should but does not summon the "unlock" dialog / login-screen (or at least the "shield" / lock-screen), and the screen remains blank. Also, <Ctrl><Alt><F2> is able to switch to the 2nd VT.

If in step 2, instead of doing nothing, I move the mouse sooner than the screen turns blank, then I can log in as usual.


There is one error message in the journal that seems to reappear every time this problem happens:

gnome-session: Gjs-Message: JS LOG: Ignored exception from dbus method: Gio.IOErrorEnum: GDBus.Error:org.gnome.SessionManager.GeneralError: Unable to uninhibit: Invalid cookie

(Should I have filed this under gnome-session then? This is hard..)

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gnome-shell 3.10.3
gnome-session 3.10.1
gdm 3.10.0.1
Also I do not use gnome-screensaver.