The "We'll actually autofocus the playlist once you hit up/down (meaning: we'll also automatically show it, even if it was hidden, when you hit the shortcut)." feature is strange and should be removed. To see what I mean: play a movie, switch to fullscreen, hit 'down' and then 'space'. You should see that the stream gets restarted, and there is no obvious way to hide the playlist. I would suggest that there be no 'autofocus playlist' when hitting 'down/up' while the stream is focused.
I have tweaked the functionality for this in git master. Up/Down and Enter will not do anything if the playlist is hidden. This includes while in fullscreen. The playlist is only shown if/when multiple files are added at once or optical media is inserted. Please test and let me know what you think.
Tested GIT and looks good to me. Thanks!
Works for me too, so I'm marking this as fixed.