2017 and still no way to "reliably" now if your folders have "really" synced.
Example from today: Status says 100% - few seconds left
It's been uploading 223KB/s for the last 16 minutes (with the same status and a complete progress circle) but the history shows nothing changing. It's a total guessing game, I know you removed status icons due to issues, kind of feels like we have issues with the most fundamental file operations.