Couldn't close keyboard shortcuts pop-up with its close button

After installing from the Ubuntu 16.10 (20161008) ISO and logging in, I couldn't close the keyboard shortcuts window that popped up (which is a great behaviuor of course) using the cross button in the top-left. It closed when I launched a Terminal with Ctrl+Alt+T to report this bug, but really it should behave as expected and close when you press the close button.

Computer info:
VirtualBox Graphical User Interface Version 5.0.24_Ubuntu r108355
(I don't have access to spare hardware to test on at the moment)
Allocated 2GB RAM
Host OS: Ubuntu 16.04 LTS 64-bit
Lenovo ThinkPad X201

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: unity 7.5.0+16.10.20160906.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.8.0-21.23-generic 4.8.0
Uname: Linux 4.8.0-21-generic x86_64
.tmp.unity_support_test.1:

ApportVersion: 2.20.3-0ubuntu7
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 Oct 10 23:40:04 2016
DistUpgraded: Fresh install
DistroCodename: yakkety
DistroVariant: ubuntu
GraphicsCard: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter [80ee:beef] (prog-if 00 [VGA controller])
GsettingsChanges:
 b'org.compiz.core' b'active-plugins' b"['core', 'composite', 'opengl', 'wall', 'mousepoll', 'copytex', 'compiztoolbox', 'fade', 'grid', 'move', 'resize', 'vpswitch', 'workarounds', 'snap', 'imgpng', 'regex', 'place', 'session', 'expo', 'ezoom', 'unitymtgrabhandles', 'scale', 'unityshell']"
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
 b'org.gnome.desktop.interface' b'scaling-factor' b'uint32 1'
InstallationDate: Installed on 2016-10-10 (0 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Alpha amd64 (20161008)
Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: innotek GmbH VirtualBox
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-21-generic root=UUID=ad6787f4-42d9-4ee5-95fb-18a613878efa ro quiet splash
Renderer: Software
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/01/2006
dmi.bios.vendor: innotek GmbH
dmi.bios.version: VirtualBox
dmi.board.name: VirtualBox
dmi.board.vendor: Oracle Corporation
dmi.board.version: 1.2
dmi.chassis.type: 1
dmi.chassis.vendor: Oracle Corporation
dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr:
dmi.product.name: VirtualBox
dmi.product.version: 1.2
dmi.sys.vendor: innotek GmbH
version.compiz: compiz 1:0.9.13.0+16.10.20160818.2-0ubuntu2
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.70-1
version.libgl1-mesa-dri: libgl1-mesa-dri 12.0.3-1ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 12.0.3-1ubuntu2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-1ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160706-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-2
xserver.bootTime: Mon Oct 10 23:36:35 2016
xserver.configfile: default
xserver.errors:
 Failed to load module "vboxvideo" (module does not exist, 0)
 Failed to load module "vboxvideo" (module does not exist, 0)
 modeset(0): glamor initialization failed
 AIGLX: reverting to software rendering
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.4-1ubuntu6
xserver.video_driver: modeset