Menus flicker on Unity desktop

Binary package hint: unity

Menus do not fade out nicely as they are closed, but abruptly and with white flicker (see attached video). This happens on Unity desktop but not on Classic.

The computer is Acer D250 with Intel 945GME.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.8.8-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: wl
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,gnomecompat,compiztoolbox,regex,animation,expo,mousepoll,snap,text,vpswitch,wall,workarounds,grid,place,move,resize,imgpng,ezoom,session,staticswitcher,fade,scale,unitymtgrabhandles,unityshell,scaleaddon]
CompositorRunning: compiz
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1024x600
 edid-base64: AP///////wAGr9IwAAAAAAESAQOAFg14CrmllllXkSgfUFQAAAABAQEBAQEBAQEBAQEBAQEBUBQAQEFYLCAYiDEA330AAAAYAAAADwAAAAAAAAAAAAAAAAAgAAAA/gBBVU8KICAgICAgICAgAAAA/gBCMTAxQVcwMyBWMCAKADw=
DRM.card0.VGA.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
Date: Sat Apr 16 16:30:18 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus: bcmwl, 5.100.82.38+bdcom, 2.6.38-8-generic, i686: installed
GraphicsCard:
 Intel Corporation Mobile 945GME Express Integrated Graphics Controller [8086:27ae] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:022f]
   Subsystem: Acer Incorporated [ALI] Device [1025:022f]
LiveMediaBuild: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110413)
LiveMediaBuild_: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110413)
LiveMediaBuild__: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110413)
MachineType: eMachines eM250
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/hostname.seed boot=casper initrd=/casper/initrd.lz quiet splash --
ProcVersionSignature_: Ubuntu 2.6.38-8.42-generic 2.6.38.2
ProcVersionSignature__: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Renderer: Unknown
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/28/2009
dmi.bios.vendor: Acer
dmi.bios.version: V1.25
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: eM250
dmi.board.vendor: Acer
dmi.board.version: V1.25
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.25
dmi.modalias: dmi:bvnAcer:bvrV1.25:bd11/28/2009:svneMachines:pneM250:pvrV1.25:rvnAcer:rneM250:rvrV1.25:cvnAcer:ct10:cvrV1.25:
dmi.product.name: eM250
dmi.product.version: V1.25
dmi.sys.vendor: eMachines
version.compiz: compiz 1:0.9.4+bzr20110415-0ubuntu1
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu1
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 2:2.14.0-4ubuntu7
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7