the dash is lagging the system (on top of a flash-videos)

[Simon K]

To reproduce the bug:
1. play any video via a flash-player (I used firefox and any youtube video)
2. open the dash

What happens:
The Dash and my (Mouse-) pointer are lagging badly.
It seems like rendering with less than 5 fps

PS:
Playing a video via totem dosn't reproduce this lag.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: unity 7.0.0daily13.06.24-0ubuntu1
ProcVersionSignature: Ubuntu 3.9.0-4.9-generic 3.9.4
Uname: Linux 3.9.0-4-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.10.2-0ubuntu2
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
Date: Wed Jun 26 20:54:21 2013
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-06-17 (8 days ago)
InstallationMedia:

MarkForUpload: True
SourcePackage: unity
UpgradeStatus: Upgraded to saucy on 2013-06-17 (8 days ago)