Hi there, i use this opportunity since i have registered now, firstly to give you ONE BIG THANKS for great and rocksolid piece of software 
I have encountered this problem after i decided to transcode my collection to FLAC and use it exclusively, so now i rely solely on Vorbis Comments tags.
Since it is widely open Tag structure i am using now, i decided to use standard, recommended tags from Ogg Vorbis Documentation and some proposed fields from Extending Vorbis Comments page. Everything works fine and i am very happy with the result, except that somehow mp3tag forces me always to use YEAR and not DATE field.
I want to use DATE tag, for time track was recorded, for example: 1977-05-07
and YEAR field should be 1977. Even if i change it this way in Alt-T dialogue,
i always get 2 YEAR fields, 1977, and 1977-05-07 and no DATE field at all. So as far i understood, internally i have two DATE fields, and i can see them in for example foobar2000.
Is it possible to change this behaviour somehow so that i get freedom using Vorbis Comment tags and use two really separate fields DATE and YEAR?
I understand this is more wish then bug, and i apologize if i posted this here on wrong place.