Unity session window screenshots don't capture window, but capture hud

[Alan Pope 🍺🐧🐱 🦄]

Install unity on Artful and then login to the Unity session.

Open an application - such as a terminal
Press ALT+PrintScreen to capture the window

Expected behaviour

- get a screenshot of the window

Actual behaviour

- HUD pops up after screenshotting and the screenshot obtained is of the HUD, not the window.

In attached screenshot I tried to screenshot the browser window I'm typing this bug in, but I got a region of the top of the screen where HUD appears.

HUD Should not be triggered when doing ALT+Printscreen.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: unity 7.5.0+17.10.20170721.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.12.0-11.12-generic 4.12.5
Uname: Linux 4.12.0-11-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.6-0ubuntu5
Architecture: amd64
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity:Unity7:ubuntu
Date: Fri Aug 18 09:54:49 2017
DistUpgraded: Fresh install
DistroCodename: artful
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation HD Graphics 5500 [8086:1616] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo HD Graphics 5500 [17aa:5034]
InstallationDate: Installed on 2017-08-02 (15 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170712)
MachineType: LENOVO 20BV001BUK
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.12.0-11-generic.efi.signed root=UUID=20b4dfc6-b888-4543-b51f-3346a19a0e18 ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/27/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: JBET56WW (1.21 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20BV001BUK
dmi.board.vendor: LENOVO
dmi.board.version: 0B98417 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrJBET56WW(1.21):bd01/27/2016:svnLENOVO:pn20BV001BUK:pvrThinkPadT450:rvnLENOVO:rn20BV001BUK:rvr0B98417WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T450
dmi.product.name: 20BV001BUK
dmi.product.version: ThinkPad T450
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.13.1+17.10.20170720-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.82-1
version.libgl1-mesa-dri: libgl1-mesa-dri 17.1.4-1ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 17.1.4-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.3-1ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.9.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20170309-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2