Amir,
By definition “jspf” files are “JSP Segments” or “JSP Fragments” and are not valid JSP pages, the validator is disabled for these files as it would implicitly fail trying to validate a portion of an JSP page. You can however navigate to the JSP Editor settings in your preferences and remove the “jspf” extension from the “Fragment list”, then close and reopen the file and see if validation is now treating that file like a normal JSP page, I think the HTML validator will work for this as well… if it doesn’t let me know.