[REGRESSION] launcher icon tooltip never hides on maximized application's icon

[teo1978]

Just upgraded from 15.10 to 16.04.
As usual, finding out pathetic regressions in Unity.

Unfortunately it's not systematically reproducible. I was able to consistently reproduce it at will a matter of minutes ago after I started observing it. Now, I switched focus back and forth between a few windows and I'm no longer seeing it. So it appears to be random.

Steps to reproduce:
1) Launch an application, e.g. Google Chrome or Gedit and maximize its window
2) Move the cursor to the Launcher and over the icon of the application which is currently focus and maximized, let's say it's Gedit
=> a tooltip next to it appears with the application name, e.g. "Text Editor"
3) Move the cursor to the right, away from the Launcher into to the currently focused and maximized window without clicking anywhere

Expected: the tooltip next to the launcher icon should disappear
Observed: the tooltip next to the launcher icon remains visible

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.0+16.04.20160906-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-53.74-generic 4.4.30
Uname: Linux 4.4.0-53-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 340.98 Mon Sep 19 17:31:03 PDT 2016
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4)
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.2
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: Mon Dec 12 18:15:49 2016
DistUpgraded: 2016-12-11 22:45:13,519 ERROR got error from PostInstallScript ./xorg_fix_proprietary.py (g-exec-error-quark: Failed to execute child process "./xorg_fix_proprietary.py" (No such file or directory) (8))
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus:
 bbswitch, 0.8, 4.2.0-42-generic, x86_64: installed
 bbswitch, 0.8, 4.4.0-53-generic, x86_64: installed
 nvidia-340, 340.98, 4.2.0-42-generic, x86_64: installed
 nvidia-340, 340.98, 4.4.0-53-generic, x86_64: installed
 vboxhost, 4.3.14: added
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] 3rd Gen Core processor Graphics Controller [1025:0647]
 NVIDIA Corporation GF117M [GeForce 610M/710M/810M/820M / GT 620M/625M/630M/720M] [10de:1140] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] GeForce 710M [1025:0691]
InstallationDate: Installed on 2013-10-11 (1157 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Acer Aspire V3-571G
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-53-generic.efi.signed root=UUID=5830b30e-69e8-4bb4-8a2b-bc2b43c7414a ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: Upgraded to xenial on 2016-12-11 (0 days ago)
dmi.bios.date: 10/15/2012
dmi.bios.vendor: Acer
dmi.bios.version: V2.07
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: VA50_HC_CR
dmi.board.vendor: Acer
dmi.board.version: Type2 - Board Version
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V2.07
dmi.modalias: dmi:bvnAcer:bvrV2.07:bd10/15/2012:svnAcer:pnAspireV3-571G:pvrV2.07:rvnAcer:rnVA50_HC_CR:rvrType2-BoardVersion:cvnAcer:ct10:cvrV2.07:
dmi.product.name: Aspire V3-571G
dmi.product.version: V2.07
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 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.2
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-0ubuntu0.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Mon Dec 12 16:48:11 2016
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:
 NVIDIA(0): Failed to initiate mode change.
 NVIDIA(0): Failed to complete mode change
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.4-0ubuntu0.2