On multiple occasions I've put the correct code in and the lesson wont accept it as correct and let me move on. The preview doesn't update either.
As I don't want to look like an idiot on the internet, I then ensure that the code is right. (use hints (copy word for word the punctuation and everything), refer to old lessons, blah blah blah). When it still wont accept it, I reset the code back to the beginning of the lesson and type EXACTLY THE SAME THING IN and only then does the preview work, and the lesson accept my answer.
WHAT GIVES, MAN?