Unity dash opens on top of fulscreen windows (good) but does not react to mouse events

STR:

1. Open firefox in fullscreen by pressing F11
2. Open dash
3. Move the mouse over any icon, click it

Expected result:
Something happens

Actual result:
Nothing happens. The icons don't react on hover, the launcher cannot be clicked. Keyboard input works though.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.8.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-22.35-generic 3.2.14
Uname: Linux 3.2.0-22-generic x86_64
ApportVersion: 2.0-0ubuntu4
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: Fri Apr 6 17:23:11 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120225)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)