Menu doesn't update automagically

[Suppositoire]

Dear Maintainer,

   * What led up to the situation?
Trying to install darktable package (and some others packages few days ago, same problem) on a Debian Testing/Stretch, when a friend using Ubuntu 15.10/Unity told me he was also affected by the same update-menus problem.

   * What exactly did he do (or not do) that was effective (or
     ineffective)?
Synaptic -> install darktable -> no menu entry for darktable
(problem seems to not occur when using Ubuntu Software Center, to be confirmed)

   * What was the outcome of this action?
The package darktable was installed, but menu was not updated.

   * What outcome did you expect instead?
Menu updated.

May be there is a link with bug #152768 https://bugs.launchpad.net/ubuntu/+source/menu/+bug/152768

I also reported it to Debian Bug report logs #819028 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=819028

Sorry if this report is far from being perfect, I'm not used to the thing.

Regards. :)