Just weighing in here to say that this feature has turned into a deal-breaker for me. I’d moved from another cloud backup solution to this one and learned, the hard way, that when I un-sync something that it also deletes the files locally - not at ALL what I expected (based on experience with, say, Owncloud and spinoffs). I see now that there’s a big warning, which is an improvement, but that’s not what I need for functionality.
I paid for my license and don’t regret it, but will be moving to another solution. Good luck.