Mouse unresponsive with menu in application title bar

System Settings -> Appearance -> Behaviour

Show the menus for a window -> in the window's title bar

When the mouse hovers over the title bar, the application menu appears. However, left-clicking any of the top menu items does nothing. To be precise, the mouse pointer briefly disappears and reappears.

After left clicking various parts of the individual menu item, or another item, the relevant drop-down sub-menu will appear and behave properly. Sometimes it helps to click the window title bar to the right of the application menu, and then click the "help" menu item as soon as it appears. After one of the sub-menus has appeared, moving the mouse left or right to the menu item that is really wanted will produce the correct sub-menu.

There is no difference in sensitivity with Menu Visibility either setting: always displayed or mouse hovering.

This behaviour is NOT observed when the application menu is displayed in the desktop menu bar.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.0+16.04.20160906-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19
Uname: Linux 4.4.0-38-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
BootLog:
 lvmetad is not active yet, using direct activation during sysinit
 /dev/mapper/lvmG4-xenial: clean, 320386/2949120 files, 2415013/11796480 blocks
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
Date: Tue Oct 4 17:29:11 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
DpkgLog:

GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Caicos PRO [Radeon HD 7450] [1002:677b] (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Caicos PRO [Radeon HD 7450] [1043:3027]
MachineType: stem manufacturer System Product Name
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-38-generic root=/dev/mapper/lvmG4-xenial ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/28/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2002
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: P5LD2
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.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.:bvr2002:bd08/28/2009:svnstemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP5LD2:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: stem manufacturer
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.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.3
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+git20160325-1ubuntu1.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Tue Oct 4 11:58:49 2016
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input Logitech USB Receiver KEYBOARD, id 8
 input Logitech USB Receiver KEYBOARD, id 9
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.3
xserver.video_driver: radeon