Playing a sound file using the Play command with option "Close Play window when finished" activated doesn't close the window when finished.
It seems OK here.
Note that that checkbox is ignored if you interact with the dialog in any way (same as in 12). If you pause or rewind the file or jump to another file, the dialog will remain open until closed normally.
Yep, I now noticed that it only happened because I clicked somewhere into the progress bar. With several files selected the next file will not play automatically then. I thought it's a bug but it's the same (unexpected) behavior with v12.