> @Olaf:
> Thanks but no, that doesn't work. Nautilus doesn't start that way.
> Trying to start nautilus 3.16 with gnome-themes-standard 3.14 and
> gtk3 3.14:
The relevant part is the one about the popover menu. It seems that one
got introduced in gtk+-3.16
https://developer.gnome.org/gtk3/stable/GtkPopoverMenu.html
So you're right, you have do downgrade nautilus and probably other apps
that use latest gtk+ features. But that's only a side effect of and
not really related to the shadow problem.