Not sure if this is a bug, or unexpected behavior.
I loaded 5000 songs. I decided to try to manually only fix the albums that did not already have a release mbid as a test. I did this by sorting by mbid for album. I highlighted all the album mbids. I would assume this would allow me to perform actions on the rows that were tied to the fields I had selected. I then clicked on my brand new Close File icon I had placed in the bar, and instead of closing just those files, it closed out every single file I had loaded