As my EndNote database is growing with the years, I’m more and more missing a feature for hierachical classification of references. The features provided by groups and group sets are very limited. I’m thinking of a category tree or a hierachical tree of topics. When I drag a reference to a subtopic it should be automitically part of the top-level topic. It should be possible to assign a reference to different topics. The topics should be visible as a field in the reference dataset. That is what I’m missing.