Comment 5 for bug 1600136

So...

The problem for generic apps should be fixed. You can see some examples here:
 - https://github.com/3v1n0/indicators-examples-snaps

Basically we export to unity the proper absolute icon path, unless that's readable (so basically it can be everywhere inside the SNAP but in /tmp).
They're using remote parts indicator-<toolkit>, although I hope to include this in the desktop launchers by default.

As for some QT apps that don't use appmenu-qt, until we don't fix the Qt upstream implementation, the only workaround is to use a different TEMPDIR for them, see https://github.com/sergiusens/telegram-snap/issues/2#issuecomment-261139307.
When bug #1620442 is fixed, it might be ok to set TEMPDIR to XDG_RUNTIME_DIR for a such snap.