Thunderbird - Wrong mouse behaviour with unity at window deiconize

[igi]

Binary package hint: unity

I have FireTray extension for Thunderbird installed.
When I hide Thunderbird main window and then I restore it from FireTray tray-icon, sometimes I come to the wrong behavious shown by attached snapshot.
Basically, the mouse is not working correctly: clicking with position shown in the snapshot, the shown message is selected.
Please see how the main window is rendered in the top area (there's a "blank" row between the Gnome panel and Thunderbird main window.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.8.4-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,imgpng,gnomecompat,wall,ezoom,workarounds,staticswitcher,resize,fade,unitymtgrabhandles,scale,session,unityshell]
CompositorRunning: compiz
Date: Fri Apr 8 02:01:18 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard:
 ATI Technologies Inc RV570 [Radeon X1950 Pro] [1002:7280] (prog-if 00 [VGA controller])
   Subsystem: Micro-Star International Co., Ltd. Device [1462:0760]
   Subsystem: Micro-Star International Co., Ltd. Device [1462:0761]
MachineType: System manufacturer System Product Name
ProcEnviron:
 LANGUAGE=it_IT:en
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=d3143721-3440-4238-a103-b3913a2e3205 ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-8.41-generic 2.6.38.2
ProcVersionSignature__: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Renderer: Unknown
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/20/2006
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0801
dmi.board.name: P5GPL
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0801:bd03/20/2006:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP5GPL:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz 1:0.9.4+bzr20110407-0ubuntu2
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.1-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.1-0ubuntu3
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu3
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu6
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu6