Cannot add a second copy of COMMENT to tagpanel

I wanted to add a second copy of COMMENT (COMM) to the Tag Panel as multiline field because the standard one only shows as a dropdown.

MP3Tag won't let me. Why?

For some hack see
/t/16708/1

Thank you! That worked nicely, I went with the usrfields.ini method.
Although contrary to what that post said, the default field remained functional for me, which is perfectly fine with me and actually what I was after.