Arabic diacritics are passing the filter, giving the ability to write almost an empty title or an empty body of a post. I think it has to be filtered before submitting.
When writing Arabic and using them, they are supposed to be used with letters (on َtَoَp or ِbِoِtِtِoِm), they can never be used alone anyway. Still, when adding them alone in the title and then add some in the body, they pass the filter. When only added in the title, they will not pass the filter
Not sure if the same happens with diacritics from other languages as well.
One thing to notice, these characters are not clickable in the questions page.ََََََََِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِّّّ ََََََََِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِّّّ