I've read through some of the previous threads concerning the number of categories displayed by default, but I'm still not sure whether there is a way to do this without hacking the code. I'm afraid I'll totally break the extension if I do that - wouldn't even know where to start. Anyway, the short of it:
Is there a built-in way to show hotspots from all categories by default? And if not, will there be in an upcoming update?