You are correct. You have to edit that subroutine. Look at the code that uses the $half variable to see how it is done for two columns and modify it for 3.
I have tried this on many occassions and have never gotten it to work to my satisfaction and finally, gave up. Sorry, I have no source code available other than what you can get at
www.orphanage.com/goodstuff/hometree.html but that has a lot of "extra" stuff in it. It is an obsolete file and I will be taking it down in the near future. But that is really not what you are looking for either because it is more of a tree thing, not a category display thing.
[This message has been edited by Bobsie (edited April 22, 1999).]