UPDATE: Turns out the trick was a full system restart. Quitting and restarting the application didn't do it, but a full restart did. Cool!
Original question posted below:
I had a note sync conflict, which I resolved manually by closing all other Joplin instances on all machines, editing the file in question, syncing, deleting the copy of the note in the conflicts folder, and syncing again. (Then restarted the application to be safe.)
So now I am left with a red, bold, Conflicts notebook. Right-clicking doesn't give any option to delete (as it would with other notebooks).
How do I get rid of this? Searching Google, this forum, and the FAQ isn't giving anything obvious yet...