I know this feature but I understand the requester that he wants it done automatically for all fields of the columns and this would be a very annoying behaviour to my opinion.
Sometime ago I wrote about something similar in the Websource-result-window, which desturbs me all the time.
Tag-Quellen: Spaltenbreiten
I tried this [Ctrl] [Num] [+]-feature in the past but did not continue to use it because I don't know how to get the original width in an equal easy way.
It would be a great feature if you would not have to manually adjust all fields later to get your original design back again. So Mp3Tag should remeber the original design and restore it with [Ctrl] [Num] [-].
Or am I overlooking this feature and it is already there too?