unity-launcher shows misaligned window previews

[Rocko]

Binary package hint: unity

See attached screenshot, which shows a window preview of Firefox even though the mouse pointer and unity launcher pointer (in black) pointing to the 'Home Folder' application icon.

This happens whenever I get a window preview of an application by hovering the mouse over its icon (in this case, Firefox) and then move the mouse up to the next application icon. Unity selects the next application as soon as the mouse moves over the icon boundary, but the old application preview remains active until the mouse reaches the centre of the new icon.

In fact, it seems like you only get the preview appearing if the mouse is in the upper half of the application icon, meaning the window preview activation is probably misaligned with the icons.

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 x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 270.30 Fri Feb 25 14:34:55 PST 2011
 GCC version: gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu1)
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,decor,compiztoolbox,grid,place,imgpng,session,mousepoll,resize,vpswitch,move,unitymtgrabhandles,wall,snap,gnomecompat,regex,thumbnail,animation,workarounds,expo,ezoom,staticswitcher,fade,scale,unityshell]
CompositorRunning: compiz
CurrentDmesg: Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied
Date: Sat Apr 9 11:15:23 2011
DistUpgraded: Log time: 2011-03-20 09:19:31.967259
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus:
 nvidia-current, 270.30, 2.6.38-8-generic, x86_64: installed
 vboxhost, 4.0.4, 2.6.38-7-generic, x86_64: installed
 vboxhost, 4.0.4, 2.6.38-8-generic, x86_64: installed
GraphicsCard:
 nVidia Corporation G84 [GeForce 8600M GT] [10de:0407] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:022e]
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20100224.1)
InstallationMedia_: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20100224.1)
InstallationMedia__: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20100224.1)
JockeyStatus: xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
MachineType: Dell Inc. XPS M1530
ProcEnviron:
 LANGUAGE=en_AU:en
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=776cd2eb-157e-4c4b-b37f-9d074a6802e9 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: Upgraded to natty on 2011-04-08 (0 days ago)
dmi.bios.date: 11/19/2008
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A12
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA12:bd11/19/2008:svnDellInc.:pnXPSM1530:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: XPS M1530
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.4+bzr20110407-0ubuntu2
version.ia32-libs: ia32-libs 20090808ubuntu11
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.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
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