That makes sence, but that must be a relative new feature? I've been on levels before that was impossible to finish due to lack of something, but then it was just to play to the end or quit. It would have been nice to get some notice about it in the empty box then. Thank you for clearing this up.
I play through Facebook using Google Chrome on Windows 10, so I assume it is the latest version of the game. I do not use the Windows 10 App. Chrome got 528 points and the version is 70.0.3538.77. Clearing cache does not help.