this report has been filed here:

https://bugs.edge.launchpad.net/ubuntu/+source/gnome-keyring/+bug/618141

"On some configurations, you must enter your password to unlock the gnome-keyring, so a dialog pop ups asking for your password.

This dialog prevents the screen to lock, so after some inactivity the computer will still be unlocked. This dialog grabs all the keyboard input, but not all the mouse input, so you can still fiddle around an do bad things.

Just after the dialog is closed (cancelled or accepted) the screen is locked. If the dialog also grabbed the mouse input, this would solve the security issue. But if someone is there inputting the password, it's weird to lock the screen after some activity.

So, my proposal is simple: just lock the screen, ignoring this dialog. I can't see a reason for this dialog to be blocking the screensaver or whatever. This is causing some security and also usability issues."