I want to add new genres to (different) existing (multi) genre tags.
I have files currently tagged as "disco; 80" and "New Wave; 80" and so on, and now I want to add a new genre (batch) to these tags. In the above example, the outcome would have to be: "disco; 80; Instrumental" - "New Wave; 80; Instrumental"
I tried to leave the genre fields set to "keep" and then added the new genre with a ; separator, but that doesn't work...
How do I solve this?