I merged your new post with your previous Book of Unwritten Tales 2 thread. Please post all questions for this game in this one thread; that helps keep the forum tidy and we can follow along with your progress.
I found this information online:
You have to wait until the fox has pasted the poster in glue before turning it into a 'Rebel Poster.' Otherwise, it will not stick to the chair.
Let me know if that helps; otherwise, I will keep looking into this.