"Shouldn't the objects have disappeared instead of the writings on them having been changed?"
Is this sentence grammatically correct? If not then how can you make it grammatically correct? Can I use the perfect participle in a question? And can I use it after "instead of"? I've heard that the verbs that follow "instead of" should be verbs that end with "-ing". But what if the event after "instead of" happened in the past? What should you use?