Since upgrading to 12.10 I cannot get my screen to lock automatically. I am using GDM at home and LightDM at work and neither will lock automatically. However, when I issue CTRL + ALT + L on either system, the screen will lock as it should.
It is set to turn the display off after 5 minutes and lock screen when screen turns off. Require Password is set also. Display turns off after 5 minutes but no locking occurs.
I am using Unity with Compiz on both systems. Not sure what other things might be involved.