Application appears on different screen after wake up from suspend in multi-screen setup

When having an external screen connected to my laptop, maximised application windows sometimes appear on a different screen when waking up from suspend than they were prior to suspend.

Steps to reproduce:
1. Connect an external screen.
2. Start an application, e.g. Thunderbird and ensure it is open and maximised on the laptop's screen.
3. Suspend the laptop e.g. by closing the lid.
4. Wake up from suspend.

Expected behaviour:
The application window should appear on the same screen and in the same place as it was prior to suspend.

Actual behaviour:
The application window appears on the external screen on waking up from suspend.
Un-maximising the window revert it back to the laptop's screen and maximising it again keeps it on the laptop's screen rather than the external one.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.10.0-0ubuntu6
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
Date: Thu May 10 21:57:50 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110901)
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: Upgraded to precise on 2012-02-11 (89 days ago)