I think the color split can work for some people.
Please do not use the 
icon since it would make it too easy to confuse tags and categories.
What about some [ > subcat ]? The > would look like a chevron used in fancy Emacs or Shell powerlines.
I think the color split can work for some people.
Please do not use the icon since it would make it too easy to confuse tags and categories.
What about some [ > subcat ]? The > would look like a chevron used in fancy Emacs or Shell powerlines.