mouse over dock - everything disappears

[ewa]

when mouse over the dock the dock and all the windows disappears.
the problem is due to update of January 4th.
problem appears on intel graphic card.
ubuntu 16.04, Acer Aspire 7715z

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.10.0-42.46~16.04.1-generic 4.10.17
Uname: Linux 4.10.0-42-generic x86_64
NonfreeKernelModules: wl
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.15
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: Sun Jan 7 19:12:47 2018
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus:
 bcmwl, 6.30.223.271+bdcom, 4.10.0-28-generic, x86_64: installed
 bcmwl, 6.30.223.271+bdcom, 4.10.0-42-generic, x86_64: installed
GraphicsCard:
 Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Mobile 4 Series Chipset Integrated Graphics Controller [1025:0210]
   Subsystem: Acer Incorporated [ALI] Mobile 4 Series Chipset Integrated Graphics Controller [1025:0210]
InstallationDate: Installed on 2018-01-06 (0 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
MachineType: Acer Aspire 7715Z
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.10.0-42-generic root=UUID=c449c7fc-ff59-47b1-9402-03a64c57a069 ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/10/2010
dmi.bios.vendor: Acer
dmi.bios.version: V3.07
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Aspire 7715Z
dmi.board.vendor: Acer
dmi.board.version: V3.07
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V3.07
dmi.modalias: dmi:bvnAcer:bvrV3.07:bd02/10/2010:svnAcer:pnAspire7715Z:pvrV3.07:rvnAcer:rnAspire7715Z:rvrV3.07:cvnAcer:ct10:cvrV3.07:
dmi.product.name: Aspire 7715Z
dmi.product.version: V3.07
dmi.sys.vendor: Acer
version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.83-1~16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 17.2.4-0ubuntu1~16.04.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 17.2.4-0ubuntu1~16.04.2
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: Sun Jan 7 09:18:07 2018
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.19.5-0ubuntu2~16.04.1
xserver.video_driver: modeset

[ewa (ewa2u)]

keys Alt+Tab makes everything disappears too. doesn't work.

[ewa (ewa2u)]

duplicate of #1741502