please update the lxdm package to follow the new logic explained in the DisplayManagerRework page:
This requires shipping a systemd unit file in the lxdm package as well as changes to the .spec file.
Please ping us if you need help, or have questions.
Note that this is an accepted F18 feature, we'd be thankful if you could complete this update in time for the F18 release.
IIRC lxdm has already been patched accordingly, so I figure this can be closed again, but I wanted to have this bug so that we can keep track of this nicely in the tracker bug,
I have not yet committed my changes as I want to do this in a coordinated fashion.
Fixed in lxdm-0.4.1-3.fc18.