I've been experiencing an issue where trying to change status of tickets, clicking the ? buttons to view help info, and other things produces a blank box. Therefore I'm unable to change some important settings. I looked at some other discussions and saw people that were experiencing the same issue and fixed it by adding "cgi.fix_pathinfo = 1" to their php.ini file, however I've done that, restarted php5-fpm (which is what you should do), and it still isn't working.