Name/Password radio clicked -- users still show

Question

We're tightening security on our macs and have been changing login options from showing a list of users to showing Name and password.
On one particular machine, I logged into the admin account to make the switch and the panel in System Prefs-->Accounts-->Login Options where you would normally choose a radio button under Display Login Window As: ... was grayed out. I though that odd, so I enabled the root user, logged in as root, was able to choose the appropriate radio button and logged out.
When I came back, I was presented with what I wanted -- Name and Password boxes. But when I log in as the local user (or admin user) and Log Out (or Restart), I'm presented with the list of users again, NOT the Name/Password boxes.
Looking again at the selections as the admin, the correct selection is chosen, but the options are grayed out and I couldn't change them if I wanted.

Answer 1

OK, found it. I recalled this happened just after I bound the machine to Active Directory. I had chosen to allow administration by enterprise admins, and I guess somewhere up the line, somebody has turned on showing List of Users as the preference. I unbound, unchecked, restarted and now all is well.
Now I have to track down the network admin up the line to make sure that doesn't happen again down the road.