Ability to select the "Key" field

[JerryGoedert]

It would be nice to have the ability to select the Key field for the columns.
I also noticed that I cannot select Custom1 and Custom2 fields which Windows Media Player uses.
I put information in these fields.

[ohrenkino]

@JerryGoedert

Custom1 and Custom2 fields which Windows Media Player uses

Have you checked the extended tags dialogue Alt-T whether WMP has written these fields into the files or just into its own database.

The field for key is called INITIALKEY in MP3tag - and you can add that field to the file list and/or the tag panel, see the documentation:

Customization – Mp3tag Documentation

See also the documentation on further field names:

Tag Field Mappings – Mp3tag Documentation