Hi,
Just installed Okular using the snap package in my ubuntu 16.04 machine.
It works fine if right click a pdf and choose open with->okular.
If I open Okular I cannot use the file menu in the toolbar. If click "Open.." nothing happens and have no error in dmesg.
I am a newbie so please tell me if you any further information, I will provide. Thank you.
If can help I had Okular previously installed using apt (which if I remember well version 0.24), perfectly working, just wanted to try latest version (1.7.2)

Seems that the problem is related to filesystem permissions because the only menu entries that are not working (clicking them nothing happen) are those one that should open a file dialog, so File->Open, File->Import.., File->Save As, File->Export As.. while File->Print and File->Properties for example are working.
I have other packages installed with snap, for example VLC, that are working flawless.

Any Idea?

Apparently seems solved now, the only difference is that now I have kernel 4.4.0-157-generic while was kernel 4.4.0-154-generic before.