No mouseover effect for window buttons in Ubuntu Classic

Binary package hint: compiz

In Ubuntu Classic some windows don't have the mouseover effect for window buttons. The buttons work, but are not highlighted when hovering the mouse over them. This problem sometimes happens only for non-maximized windows and sometimes only for maximized windows; Changing to a diferent window border theme seems to sometimes switch the type of windows it affects (maximized vs non-maximized).

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: compiz 1:0.9.4+bzr20110415-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
CompizPlugins: [core,composite,opengl,copytex,imgjpeg,decor,text,move,ring,imgsvg,wobbly,regex,inotify,place,imgpng,cube,vpswitch,gnomecompat,dbus,resize,rotate,animation,resizeinfo,workarounds]
Date: Sat May 7 23:43:42 2011
DistUpgraded: Log time: 2011-05-07 20:01:32.741664
DistroCodename: natty
DistroVariant: ubuntu
DkmsStatus:
 vboxhost, 4.0.6, 2.6.38-8-generic, x86_64: installed
 fglrx, 8.840, 2.6.35-28-generic, x86_64: installed
 fglrx, 8.840, 2.6.38-8-generic, x86_64: installed
GraphicsCard:
 ATI Technologies Inc RV770 [Radeon HD 4850] [1002:9442] (prog-if 00 [VGA controller])
   Subsystem: XFX Pine Group Inc. Device [1682:5006]
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
InstallationMedia_: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
JockeyStatus: xorg:fglrx - ATI/AMD proprietary FGLRX graphics driver (Proprietary, Enabled, In use)
MachineType: System manufacturer System Product Name
PackageArchitecture: all
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=50e89cbf-fe3a-4f47-a2a0-5417c37415b4 ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Renderer: Unknown
SourcePackage: compiz
UpgradeStatus: Upgraded to natty on 2011-05-07 (0 days ago)
dmi.bios.date: 05/19/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0504
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: P6T DELUXE V2
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.:bvr0504:bd05/19/2009:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP6TDELUXEV2: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+bzr20110415-0ubuntu2
version.fglrx-installer: fglrx-installer N/A
version.ia32-libs: ia32-libs 20090808ubuntu13
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu2
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 2:2.14.0-4ubuntu7.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7