Minimizing the window leaves some remains of the minimization process in the desktop

[Guruprasad]

When I minimize a window, the remnants of the window minimization process, like title bar and the window shrinking in size to an icon show up on the desktop. In the attached screenshot, thunderbird title bar remnants during the actual minimization show up near the unity menu.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: thunderbird 7.0~b2+build2+nobinonly1-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-11.17-generic 3.0.4
Uname: Linux 3.0.0-11-generic i686
NonfreeKernelModules: nvidia
AddonCompatCheckDisabled: False
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.22.1-0ubuntu2
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: guruprasad 1647 F.... pulseaudio
BuildID: 20110906005012
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf8400000 irq 47'
   Mixer name : 'Realtek ALC268'
   Components : 'HDA:10ec0268,103c30cc,00100003 HDA:10573055,10573055,00100700'
   Controls : 21
   Simple ctrls : 13
Channel: default
Date: Mon Sep 12 21:39:16 2011
ForcedLayersAccel: False
IfupdownConfig:
 auto lo
 iface lo inet loopback
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110901)
IpRoute:
 default via 192.168.1.1 dev wlan0 proto static
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.8
Prefs:
 places.database.lastMaintenance - 1315744866
 extensions.lastAppVersion - 7.0
 network.cookie.prefsMigrated - true
 places.history.expiration.transient_current_max_pages - 63317
ProcEnviron:
 LANGUAGE=en_IN:en
 PATH=(custom, no user)
 LANG=en_IN
 SHELL=/bin/bash
Profiles: Profile0 (Default) - LastVersion=7.0/20110906005012 (Running)
RunningIncompatibleAddons: False
SourcePackage: thunderbird
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/25/2008
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.59
dmi.board.name: 30CB
dmi.board.vendor: Quanta
dmi.board.version: 79.2E
dmi.chassis.type: 10
dmi.chassis.vendor: Quanta
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.59:bd11/25/2008:svnHewlett-Packard:pnHPPaviliondv9700NotebookPC:pvrRev1:rvnQuanta:rn30CB:rvr79.2E:cvnQuanta:ct10:cvrN/A:
dmi.product.name: HP Pavilion dv9700 Notebook PC
dmi.product.version: Rev 1
dmi.sys.vendor: Hewlett-Packard