The question I'm looking at says "Tu ne veux pas savoir ________ je pense de ton costume" and the correct answer indicated is "ce que." However, because it's "... _______ je pense DE" shouldn't it be "ce dont?"
Similar examples would be:
"Tu sais ce dont je suis capable."
"C'est ce dont j'ai peur."
"Je ne sais pas à quoi tu penses." (This is 'penser à' instead of 'penser de')
What am I missing here?