Comment 1 for bug 1204599

We use libgnome-menu to build the applications index and watch for changes, so that is where the bug probably resides.

The configuration we use is in /etc/xdg/menus/unity-lens-applications.menu and uses the <DefaultAppDirs/> directive to pick applications directories rather than specify them manually.

Perhaps it only checks for these default directories once on startup, rather than watching the parents of missing default dirs?