moving icons on the desktop leaves some garbage

[LGB [Gábor Lénárt]]

I'm using Unity-2D with metacity (composite effects are on). I also switched on icons on the desktop (computer, home, mounted filesystems), but I have custom ones too. If I want to move an icon by dragging it, ugly garbage is left on the screen where I move that icon. The garbage disappears if I click onto some of the unused part of the desktop though. For sure, it's not a show-stopper bug, but looks quite ugly.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: metacity 1:2.34.1-1ubuntu11
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic-pae 3.2.13
Uname: Linux 3.2.0-21-generic-pae i686
ApportVersion: 2.0.1-0ubuntu2
Architecture: i386
Date: Thu Apr 12 17:54:13 2012
InstallationMedia: Ubuntu-Server 10.04.1 LTS "Lucid Lynx" - Release i386 (20100816.2)
SourcePackage: metacity
UpgradeStatus: Upgraded to precise on 2012-03-01 (41 days ago)