When fixing tags in M4A files, I can't see the total track part of the TRACK tag. All my MP3 files have X/Y in that field, but M4As only have X.
Interestingly, if I use the Auto Numbering Wizard and put a random Y in the total count box and check that it be saved, it is. When I reload the files in iTunes, they have the new value.
So, I can change it, I just can't see it. What am I missing?