Docking 2 window together in a multi-screen setup not working

[Moc]

Binary package hint: unity

In a Multi-Screen with horizontal screen distribution, you can dock a window only to the far left of left screen, and the far right of the right screen.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.6.6-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-7.36-generic 2.6.38
Uname: Linux 2.6.38-7-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 4.5.2-6ubuntu4)
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,snap,vpswitch,move,gnomecompat,place,regex,grid,mousepoll,resize,wall,imgpng,animation,session,expo,workarounds,ezoom,staticswitcher,fade,scale,unityshell]
CompositorRunning: compiz
Date: Sun Mar 20 18:52:38 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus: nvidia-current, 270.30, 2.6.38-7-generic, x86_64: installed
GraphicsCard:
 nVidia Corporation GT218 [NVS 3100M] [10de:0a6c] (rev a2) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:040a]
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110319)
InstallationMedia_: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110319)
InstallationMedia__: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110319)
JockeyStatus: xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
MachineType: Dell Inc. Latitude E6410
ProcEnviron:
 LANGUAGE=en_CA:en
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-7-generic root=UUID=e7cdc686-96c3-42ba-be27-a7f90e87b8fa ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-7.36-generic 2.6.38
ProcVersionSignature__: Ubuntu 2.6.38-7.36-generic 2.6.38
Renderer: Unknown
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/10/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A05
dmi.board.name: 0K42JR
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA05:bd08/10/2010:svnDellInc.:pnLatitudeE6410:pvr0001:rvnDellInc.:rn0K42JR:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6410
dmi.product.version: 0001
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.4-0ubuntu7
version.libdrm2: libdrm2 2.4.23-1ubuntu5
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 1:7.6~3ubuntu11
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu6