Since the newest Mp3tag v3.19a you can set the tag field size in the tag panel to "Tiny" ("Winzig").
I tested that on a new Windows 10 and with the standard Mp3tag (32bit).
After changing the tag field size for Year, Track and Genre to tiny in one go, Mp3tag crashed.
It is not possible to start it again, I only get this message:
Mp3tag.dmp (92,4 KB)
PS: This was in a test environment only. I had to delete the userfields.ini in
to get Mp3tag starting again.