Icon gets overprinted on focus at folder preview (and perhaps others)

[Dario Ruellan]

Hardware: https://wiki.ubuntu.com/druellan/hpenvy1095la

Test case:
On Ubuntu 12.10 beta2, <super>f to open the file lens
Right-click on documents
Hover in and out of the open button or the right arrow a couple of times.
The shadow and the alpha blending of the icon start to fill in, usually meaning that a copy of the icon has been placed over the old one. This seems to happen every time you hover (check attach).

You can also watch this effect while using the arrow keys to navigate the preview (subtle but its there).

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: unity 6.6.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-15.23-generic 3.5.4
Uname: Linux 3.5.0-15-generic i686
.tmp.unity.support.test.0:

ApportVersion: 2.5.2-0ubuntu4
Architecture: i386
CasperVersion: 1.324
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Sun Sep 30 18:30:04 2012
DistUpgraded: Fresh install
DistroCodename: quantal
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:1436]
 Advanced Micro Devices [AMD] nee ATI Madison [Radeon HD 5000M Series] [1002:68c1] (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:1436]
LiveMediaBuild: Ubuntu 12.10 "Quantal Quetzal" - Beta i386 (20120926)
MachineType: Hewlett-Packard HP ENVY 14 Notebook PC
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: initrd=/ubninit file=/cdrom/preseed/username.seed boot=casper quiet splash -- BOOT_IMAGE=/ubnkern
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/01/2011
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.26
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 1436
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 59.24
dmi.chassis.asset.tag: CNU0250TQZ
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.26:bd12/01/2011:svnHewlett-Packard:pnHPENVY14NotebookPC:pvr0492100000241910000620000:rvnHewlett-Packard:rn1436:rvr59.24:cvnHewlett-Packard:ct10:cvrChassisVersion:
dmi.product.name: HP ENVY 14 Notebook PC
dmi.product.version: 0492100000241910000620000
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.8.2+bzr3377-0ubuntu1
version.libdrm2: libdrm2 2.4.39-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.0~git20120917.7cfd42ce-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.0~git20120917.7cfd42ce-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.13.0-0ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.99.99~git20120913.8637f772-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.20.8-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.2-0ubuntu1