answer:It depends what you are trying to hide. It could be spam or a Facebook virus you have accidentally clicked on – these will constantly repost themselves, no matter how many times you hide them. Try closing the Facebook tab, then refreshing the page a while later and trying again. If this is a virus, then you can simply get rid of it by going to the application’s setting page and deleting the app. Alternatively, it could just be Facebook malfunctioning and being slow to respond to your request. Just keep trying and keep refreshing. They could have actually been deleted to everyone else’s view, but could still show on your personal account.