Screen scaling slider does not update display when using cursor keys

[Chris Bainbridge]

Click on the scaling slider in the monitors settings, then press the left or right cursor keys to move it. The slider moves, but the scale used by the display does not change (dragging and releasing does work).

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity-control-center 14.04.3+14.04.20140410-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Apr 16 13:45:52 2014
InstallationDate: Installed on 2014-03-27 (19 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Beta amd64 (20140326)
SourcePackage: unity-control-center
UpgradeStatus: No upgrade log present (probably fresh install)
usr_lib_unity-control-center:
 activity-log-manager 0.9.7-0ubuntu14
 deja-dup 30.0-0ubuntu4