User created via python-libuser not shown in login screen or System Settings -> User accounts

[Erkki-T. Peura]

$ grep foobar /etc/passwd
$ echo $?
1
$ sudo python
Python 2.7.5+ (default, Sep 19 2013, 13:48:49)
[GCC 4.8.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import libuser
>>> admin = libuser.ADMIN()
>>> user = admin.initUser("foobar")
>>> user.set(libuser.UIDNUMBER,"99999")
>>> user.set(libuser.GIDNUMBER,"99999")
>>> admin.addUser(user)
1
>>>
$ grep foobar /etc/passwd
foobar:x:99999:99999:foobar:/home/foobar:/bin/sh

'foobar' can login in terminal (alt-f1 etc) but it's not shown on lightdm login window nor on System settings -> User accounts
(doesn't make difference if dialog is locked/unlocked)

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: python-libuser 1:0.56.9.dfsg.1-1.2ubuntu2
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Fri Nov 8 14:22:43 2013
InstallationDate: Installed on 2013-11-08 (0 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
SourcePackage: libuser
UpgradeStatus: No upgrade log present (probably fresh install)

[Erkki-T. Peura (erkki-t-peura)]

Not related to libuser, check /etc/login.defs UID_MAX