Pressing super+s shows the workspace switcher, even when there is only one workspace

What happens:
On Ubuntu 13.04, by default, there is only one workspace enabled. But when you press super+s you Unity shows the workspace switcher with one workspace. (see screenshot)

What should happen:
If there only is one workspace, pressing super+s should do nothing.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: compiz 1:0.9.9~daily13.04.18.1~13.04-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-19.30-generic 3.8.8
Uname: Linux 3.8.0-19-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
Date: Fri May 3 16:10:44 2013
DistUpgraded: Fresh install
DistroCodename: raring
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) [8086:2a02] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: Toshiba America Info Systems Device [1179:ff50]
   Subsystem: Toshiba America Info Systems Device [1179:ff50]
InstallationDate: Installed on 2013-04-26 (6 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: TOSHIBA Satellite Pro U400
MarkForUpload: True
PackageArchitecture: all
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-19-generic root=UUID=db950c91-300f-45a3-ac57-776460ec2a49 ro quiet splash vt.handoff=7
SourcePackage: compiz
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/12/2008
dmi.bios.vendor: TOSHIBA
dmi.bios.version: V3.00
dmi.board.name: Satellite Pro U400
dmi.board.vendor: TOSHIBA
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: TOSHIBA
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnTOSHIBA:bvrV3.00:bd07/12/2008:svnTOSHIBA:pnSatelliteProU400:pvrPSU41E-002002DU:rvnTOSHIBA:rnSatelliteProU400:rvrNotApplicable:cvnTOSHIBA:ct10:cvrN/A:
dmi.product.name: Satellite Pro U400
dmi.product.version: PSU41E-002002DU
dmi.sys.vendor: TOSHIBA
version.compiz: compiz 1:0.9.9~daily13.04.18.1~13.04-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.43-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.1.1-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.1.1-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.13.3-0ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2b2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.1.0-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.6-0ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.7-0ubuntu1
xserver.bootTime: Fri May 3 15:47:20 2013
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.13.3-0ubuntu6
xserver.video_driver: intel