I don't know if this has been suggested before, or if such a feature has been realized with a plugin already, but since I didn't find anything:
I would like all tag-fields (or at least all tag-fields with text input) such as grouping, track title, publisher and the custom fields to have drop-down lists like the artist, album, conductor, composer, etc. fields already have.
I collect classical music, with lots (lots!) of groupings (I use this field for sorting opus), orchestras (I specified one of the custom fields as such) and even tracks being identical, i.e. when I have several recordings of the same opus by various artists.
It would be a hugely appreciated, if MediaMonkey would suggest the correct grouping, custom field and title entries - I wouldn't have to be so tedious about correct spelling of these crackjaw opus names.

Best regards and thank you for this wonderful piece of software (which releases me of the clinches of iTunes),
kathyj