Comment 65 for bug 1532226

So, unfortunately it's quite hard to reproduce this issue here (I can't get either in VMs and in two laptops), so we need some debug hints in your side.

I've prepared a ppa with a version of indicator-appmenu that includes some debugging bits. Just add this ppa:
  ppa:3v1n0/xenial-missing-menus-tests

Install indicator-appmenu from there, and once this issue shows up, please send us your copy of
  ~/.cache/upstart/unity-panel-service.log

You can then revert the change by using ppa-purge or just:
  sudo rm /etc/apt/sources.list.d/3v1n0-ubuntu-xenial-missing-menus-tests-xenial.list
  sudo apt-get install indicator-appmenu/xenial

Thanks.