Show menus in a windows menu bar does not work well or consistently

What tends to happen to many users is the menus don't expose except thru repeated attempts.
This appears to be due to the default value of 175 for com.canonical.Unity.Decorations grab-wait.
175 is probably too low (fast) for use of the menus unless users click very fast & promptly.

Solutions -
1. raise the default to something that works for both global & in window
2. when enabling the option write a higher value to user's dconf settings
350 - 500 seems to work for most users

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.0+16.04.20160906-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-49.70-generic 4.4.30
Uname: Linux 4.4.0-49-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset 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 367.57 Mon Oct 3 20:37:01 PDT 2016
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4)
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
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 Nov 21 17:34:16 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus:
 bbswitch, 0.8, 4.4.0-49-generic, x86_64: installed
 nvidia-367, 367.57, 4.4.0-49-generic, x86_64: installed
GraphicsCard:
 Intel Corporation 4th Gen Core Processor Integrated Graphics Controller [8086:0416] (rev 06) (prog-if 00 [VGA controller])
   Subsystem: Lenovo 4th Gen Core Processor Integrated Graphics Controller [17aa:3801]
 NVIDIA Corporation GK107M [GeForce GT 755M] [10de:0fcd] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Lenovo GK107M [GeForce GT 755M] [17aa:3801]
GsettingsChanges:
 b'org.compiz.core' b'active-plugins' b"['core', 'composite', 'opengl', 'copytex', 'snap', 'resize', 'regex', 'commands', 'move', 'place', 'grid', 'imgpng', 'animation', 'vpswitch', 'wall', 'compiztoolbox', 'mousepoll', 'session', 'workarounds', 'unitymtgrabhandles', 'expo', 'fade', 'ezoom', '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 2016-11-16 (4 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Beta amd64 (20161115)
MachineType: LENOVO 20217
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-49-generic.efi.signed root=UUID=789b6c48-9545-46ff-9dc8-f344e61e9165 ro quiet splash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/18/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 74CN44WW(V3.05)
dmi.board.asset.tag: No Asset Tag
dmi.board.name: VIQY0Y1
dmi.board.vendor: LENOVO
dmi.board.version: 31900058STD
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo IdeaPad Y510P
dmi.modalias: dmi:bvnLENOVO:bvr74CN44WW(V3.05):bd09/18/2013:svnLENOVO:pn20217:pvrLenovoIdeaPadY510P:rvnLENOVO:rnVIQY0Y1:rvr31900058STD:cvnLENOVO:ct10:cvrLenovoIdeaPadY510P:
dmi.product.name: 20217
dmi.product.version: Lenovo IdeaPad Y510P
dmi.sys.vendor: LENOVO
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 Nov 21 17:33:48 2016
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.4-0ubuntu0.2