This is a sanity check for newer users and is the default initially. It also affects editing of fields such as Title which are unique for each track.

If you Go to Preferences-File List and uncheck 'Disable Unique Fields on Multiple Selections' the test will be disabled.

When Yate first came out I had users who would select a bunch of files, then edit the Title field assuming that only the first would be changed. People were also loading up dozens of albums and editing the artwork and messing up. When the option is set, the Artwork panel disables itself when more than one folder is loaded.

That makes sense for novice users, thanks for adding the message! Real great to see such fast response to issues. Am still in testing mode, might be time to buy a license. 😉