Dash and Launcher transparency does not work on Ubuntu 14.04.5

Dash and Launcher transparency does not work on Ubuntu 14.04.4 / 14.04.5

it works perfectly on Ubuntu 14.04.1 / 14.04.2 / 14.04.3 ! ! !

i think xserver/xorg bug

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: compiz-core 1:0.9.11.3+14.04.20160425-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-31.50~14.04.1-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Thu Jul 28 15:29:21 2016
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
ExecutablePath: /usr/bin/compiz
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM] [1002:6779] (prog-if 00 [VGA controller])
   Subsystem: PC Partner Limited / Sapphire Technology Device [174b:e204]
InstallationDate: Installed on 2016-07-27 (0 days ago)
InstallationMedia: Ubuntu 14.04.5 LTS "Trusty Tahr" - Beta amd64 (20160727)
MachineType: System manufacturer System Product Name
ProcEnviron:
 LANGUAGE=fr_FR
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-31-generic root=UUID=fc7c12fa-8387-42ed-95ec-d4b90af46e1d ro quiet splash vt.handoff=7
SourcePackage: compiz
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/05/2008
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0709
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: M2N-VM HDMI
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev x.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.:bvr0709:bd12/05/2008:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnM2N-VMHDMI:rvrRevx.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz 1:0.9.11.3+14.04.20160425-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.14.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri N/A
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Thu Jul 28 14:46:03 2016
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input AT Translated Set 2 keyboard KEYBOARD, id 8
 input ImExPS/2 Generic Explorer Mouse MOUSE, id 9
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.2~trusty1
xserver.video_driver: radeon