You can also open and close the "Playlist" window by grabbing and dragging the very edge of the lower right corner of controller window.
At a certain shape and size, the "Playlist" window will snap opened or closed as appropriate.
Over the last few months, we’ve received a number of requests for assistance on a Word Press Media Library-related issue.
Specifically, Word Press users were reporting that their Media Library image files weren’t showing up as proper thumbnails – it seemed as if the thumbnails were missing.
(Users have reported files playing in random order even when they don't want them to.