@kyonichisama: My understanding is that she didn't officially and legal "renounce" her claim, but rather that she chose to not pursue her claim and make it plain that she supports her brother's claim.
That said, legal situations regarding that sort of thing are murky. Even though renouncing one's claim legally is supposed to be the final step to show absolutely that that person will never take the throne, there are a number of precedents in fiction and I believe in real life where circumstances changed and the person who had stepped down ended up becoming the ruler anyway. In this case, if the prince continues to screw up to the point that the king remvoes him from the sucession or outrights disowns him (or, for that matter, if he dies without an heir), then putting Anne-Sophia on the throne would be viewed by many as the best option, despite her own dislike for the idea.
