Unity interface is garbled when running in VirtualBox

Just installed Precise alpha to VirtualBox. The default Unity interface gets garbled - windows do not disappear after they are closed. Other than this GUI works OK.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.4.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-17.26-generic 3.2.6
Uname: Linux 3.2.0-17-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 1.92-0ubuntu1
Architecture: amd64
CompizPlugins: [core,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,imgpng,gnomecompat,wall,ezoom,workarounds,resize,fade,unitymtgrabhandles,scale,session,unityshell]
CompositorRunning: compiz
CrashDB: unity
CurrentDmesg:
 [ 30.838021] audit_printk_skb: 39 callbacks suppressed
 [ 30.838023] type=1400 audit(1329911590.813:24): apparmor="DENIED" operation="open" parent=1 profile="/usr/lib/telepathy/mission-control-5" name="/usr/share/gvfs/remote-volume-monitors/" pid=1717 comm="mission-control" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
 [ 340.744435] hrtimer: interrupt took 850797627 ns
 [ 340.744480] sched: RT throttling activated
Date: Wed Feb 22 16:41:03 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
GraphicsCard: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter [80ee:beef] (prog-if 00 [VGA controller])
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120222)
Lsusb:
 Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet
MachineType: innotek GmbH VirtualBox
ProcEnviron:
 TERM=xterm
 PATH=(custom, no User Name)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-17-generic root=UUID=392c39c4-7a64-4ba1-860a-f60aac9e696e ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/01/2006
dmi.bios.vendor: innotek GmbH
dmi.bios.version: VirtualBox
dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:
dmi.product.name: VirtualBox
dmi.product.version: 1.2
dmi.sys.vendor: innotek GmbH
version.compiz: compiz 1:0.9.7.0~bzr2995-0ubuntu4
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.30-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0~rc2-0ubuntu5
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0~rc2-0ubuntu5
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.99.901+git20120126-0ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2