I would expect one of two behaviors when, in my library window, I search something like this
publisher:
I would expect either (1) everything to show up (because each volume in my library has at least no character in the publisher field), or (2) I would expect only titles that have no publisher listed. However, the search returns 13 results (out of over 4,000 volumes), as shown below.

Can anyone explain this result? Thanks in advance.
Lew