Sometimes it doesn't pay off to be smart and write the best possible code. Good code can be slow and bad code can be fast.
The Treectrl widget which is a core part of the Coccinella came with a 2.2 release a couple of months ago, and this included support for the much awaited tags. Each item can have a list of more or less arbitrary tags instead of being referenced with just a number, which may change if items are recreated. Previously I just kept an array that mapped tag to item number.