Comment 103 for bug 1311316

I cannot imagine how a missing password input field in the lock screen could be related to an LDAP configuration issue on our side.
If the authentication would fail after entering the password, then yes, of course this could be such a problem.
But a password field should always be shown by the unlock screen, regardless of the authentication backend.

Also our LDAP configuration is working for several years now without problems.
Only since the upgrade to Ubuntu 14.04 this problem with the lock screen has started appearing.
All other applications, including the login screen (lightdm) are working fine.

By the way, we have a dual monitor setup, too.
Our home file systems are on an NFS fileserver, mounted using automount and with root_squash enabled (this means that root does not have full access to my home directory, but only the same rights as all other accounts). If there is a root process trying to access files in my home this would fail.