I made a few edits to track information in Banshee's File System Queue playlist, and it appeared nice. However, the Artists box (in the middle of the screen) contained old information (as it was before my edit).
I thought this would get fixed if I select
Tools -> Rescan Media Library. I got a brief message with '100% complete' status, however list of artists (which was modified and changed) remains as it was.
I have no clue what this means and how to really re-scan the library.