Instant visual feedback missing when shutting down the computer

Steps to reproduce:

1) From the power/settings menu select "Shut Down..." so that the Shut Down dialog opens
2) Click on Shut Down or Restart buttons

What should happen:
- There should be instant visual feedback indicating that the shut down / restart is in progress and that the users click on the Shut Down dialog was accepted.

What happens instead:
- Especially on slower computers it seems that nothing happens. It seems that everything is just stuck. On my computer it can take 20-30 secs before the desktop and Shut Down dialog goes away. Before this phase only thing indicating that something is happening is the distant sound of my hard drive.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: unity 6.12.0daily13.03.25.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-15.25-generic 3.8.4
Uname: Linux 3.8.0-15-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.9.2-0ubuntu5
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: Sat Mar 30 14:39:08 2013
InstallationDate: Installed on 2012-10-19 (161 days ago)
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: Upgraded to raring on 2013-01-20 (68 days ago)