For sanity and clarity in a hectical multi project work day, it would be great to be able to group things together by project. Unfortunately right now, that can only be done on creation of the document and not in retrospect.
As we still use the hosted version I cannot see how the tables look in the db. Guessing that one would need to either add a project ID to the document or add the document ID to the project, I would imagine this to be at least possible.