iTunes 12 features a new Info window, which displays when you select one or more tracks and press Command-I. In this window, you can edit tags, such as album, artist, composer, etc. There is one tag, however, where you’re limited in how you can edit it: the Comments tag.
In this file, I wanted to add some info to the Comments field; I wanted to add the names of the musicians in the band. In the above screenshot, I’ve selected that field (and you can see that there’s a bug in the way the window displays when the filed is selected, cutting off the text below it).
I got the file with the comments included. In iTunes 12, I can’t edit those comments, I can’t add anything to the field, I can only delete them. But, there’s a way to do this. Instead of pressing Command-I, press and hold the Option key, then right click and choose Get Info. You’ll see the old style Info window.
Here, I was able to add info, and edit it. One note: to add a return character in that field – to create a blank line – press Option-Return.