Nicole I agree with you but I would like to add something.
I think the authors are talking mainly about creativity. Thinking outside the box. Providing something new and different. I also feel they are talking specifically about an eclipse of creativity implying maybe that even if there is something already there (a creative thought) , teachers, family and friends could discourage us from the expression of this creative though in such an extent that the thought will eclipse.
So in essence, I think they refer to the expression of creative though , and not just expression as would be used in a general way.