Cannot switch displays in System Settings > Displays

[Colin Law]

Running Quantal alpha up to date on dual display system.
To replicate:
Open System Settings > Displays. The Displays window appears showing both displays, with one of them selected.
Click the icon for the other display, it should become selected, but is not.
Drag the Displays window to the other display, switch to All Settings and back to Displays, now the other display is selected but again one cannot switch between them.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gnome-control-center 1:3.4.2-0ubuntu6
ProcVersionSignature: Ubuntu 3.5.0-7.7-generic 3.5.0
Uname: Linux 3.5.0-7-generic i686
ApportVersion: 2.4-0ubuntu6
Architecture: i386
Date: Sun Aug 5 09:42:46 2012
ExecutablePath: /usr/bin/gnome-control-center
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120730.1)
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
SourcePackage: gnome-control-center
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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