It is regression, thanks for reporting, fixed as https://www.ventismedia.com/mantis/view.php?id=15796

Just a question about a lost feature:

Is there a way to re-activate the old feature of automatic gathering pictures of artist, composer,etc.?
Actually, It only works when you double click to go into a composer or artist screen, whereas before, MM5 was always scannig for missing images.

Many thanks