Can't delete playlist from queue

What a great thing this is for my classroom. Thanks for all your efforts.

I’m not able to remove playlists from the queue. I can clear the queue if it contains music selected from my library as individual songs, or as albums folders, or folders with subfolders, but cannot clear queue if I have added a playlist to it.

I can make playlists from my music. I can add the playlist to the queue. But when I try to delete the playlist from the queue or use the clear and replace from the music library / playlist area, the queue does not clear. I can no longer play music until I reboot. I cannot restart from the system from software and must unplug power in order to reboot effectively.

It seems from the Web interface that the PI is not locked up, but could that be the browser cache?

0.978 Running on Raspberry Pi 3. Internal wifi. Music on USB thumb drive plugged directly to PI. Hifiberry Plus is installed, but I need to control volume remotely, so I’m using a USB Dragonfly (also attached directly) for now until I get something that fits in the case.