This is my first post. I don't know how many other people have discovered this bug, but this seemed the logical place to share my experience.
Upon starting Visual Studio there is, on occasion, a bug which prevents the backspace and return keys to stop working. Initially when I restarted, the bug stopped. I have since discovered that if you push alt-return (the normal combination to toggle full-screen apps) it returns the focus to the correct windows and the keys work again.
Hope that helps!