Obviously Sentoss had in mind the case of مَنْ ("who") and مِنْ ("from"). Can searching be made diacritic-sensitive? This way, when searching for مَنْ for example, the search-result page won't show مِنْ together with مَنْ.
MS Word and LibreOffice Writer ignore diacritics unless a certain option is selected. Search engines also ignore them, unless the option VERBATIM is used in Google search. However, when these options are on, they won't be able to do a partial matching of the diacritics. For example, فَتحة won't find فَتْحَة and فُتحة won't find فُتْحَة.