Just to Add - It would be nice to be able to add support for any tag (I use rapid evolution - so theres key, beat intensity and probably one or two others that would be nice to have..)

Oh and the ability to have it as a treenode is the most important thing...

(apologies if i'm being dense but I can't see how to do it!)

Many people use the grouping tag for a variety of reasons. I myself use it for categorisation of release type: Singles, Compilations, Albums, Unreleased tracks, Demos and sub categories of: Vinyl, CD, Digital A-sides,B-sides etc It would be really useful if the multiple value support (using semi-col...