He is not complaining that the file can or cannot be backed up, and Dropbox is no backup service by the way. He is complaining that their software hangs on ope

He is not complaining that the file can or cannot be backed up, and Dropbox is no backup service by the way. He is complaining that their software hangs on open file instead of doing the sensible thing and not using 100% cpu until the lock goes away. That has nothing to do with "how computers work".