Favourites enhancement

Hi, and thanks for writing such a useful tool!

I was wondering if there would be a way to add separators to the favourites list?

Currently, I have a large (ish) list of expressions which can be quite hard to read, so I use a hyphen as a fake seperator to break the list up: hyphen as the name, and %f as the expression, so if I click on it, nothing will happen to the name.

It would be nice if you could use an underscore character (like you do in regular programming) to create an un-clickable seperator line in the dropdown menu.

What would also be nice to have is the ability to add cascading submenus, so you could group items into sublists.

I don't know if that's possible, but it sure would be handy.

Thanks for reading