Hi,
mp3tag is a superb app, I like the way it's so simple to use yet is very powerful when you delve deeper. It's saving me so much time I have donated today, keep up the good work.
One suggestion I have is that I do a lot of tag and filename conversions, and typing out the field names or editing an existing string in the cache can be time consuming. I thought a simple drop down underneath the entry box that lists the field names (Artist, Title etc) could be used to quickly enter the required string.
Thanks
ner