Here are some things I've noticed when searching:

I have a collection titled 'Sixties Classics' that contains a song titled 'The Letter' written by 'Wayne Carson Thompson'. I entered Thompson's name and the role 'Songwriter' on the Authors and Performance list inside the Credits property sheet of the Tracks property page. This is a box set containing (so far) two albums). Wayne Carson Thompson is also credited as songwriter on another album (Sounds of the Seventies - 1970) that is not a box set.

When I use the advanced search Tracks tab, where Field = "Author", Condition = "is (exactly)" and Value = "Wayne Carson Thompson", then press Add to List and Search I get no results. I verified that there were no spaces before or after his name and the spaces between his names as well as the capitalization matched.

When I change the Condition to "contains" (and retype the Value "Wayne Carson Thompson") it returns every track on the single album (Sounds of the Seventies - 1970) despite the fact that Wayne Carson Thompson is credited as a songwriter on only one track. It does not return any results from the box set "Sounds of the Sixties." I have noticed that in single albums, the album page shows the credits and identifies the tracks, but in box sets the credits page simply says "(various)". I wonder if that could be related?

When I set the Field to [any field] and the Condition to contains I get no results at all.

It seems that either there is a bug in the search, or I am doing something wrong. Any help would be appreciated.