Had the same issue here http://forum.espruino.com/conversations/376829/ and somehow goofed it out eventually.
It was an issue with the Layout library that existed for I think about 48 hours - if you were unlucky enough to update during that time then you got the problem.
So all you need to do is uninstall and reinstall messages (or if the version has already changed, update it again)
I am surprised no one has posted this before, I feel like I have missed it. But for a while now I can not use the Messages app at all. It shows a white screen (the widgets are drawn, rest is white) whenever it is trigger by the Bangle JS app or when I open it with the menu when a notification is unread. The no messages screen is drawn correctly.