When using an external monitor, LightDM uses a low resolution on both

[Kazade]

I have a laptop with a screen resolution of 1366x768 and an external 24" monitor which has a native resolution of 1920x1080.

LightDM mirrors the image on both screens, however the resolution for both screens falls back to something low, like 1024x768. I think this is probably the highest resolution that both monitors are capable of, but it has the result of the login screen looking bad on both.
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ApportVersion: 1.23-0ubuntu1
Architecture: amd64
DistroRelease: Ubuntu 11.10
EcryptfsInUse: Yes
Package: lightdm 0.9.7-0ubuntu2
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Tags: oneiric
Uname: Linux 3.0.0-11-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Kazade (kazade)]

apport information

[Kazade (kazade)]

apport information

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.