trouble with current_filter()

I have searched the forums and looked at the WordPress code that uses the function current_filter() but when I call it nothing is returned. I need to know which action/filter hook is currently active as I am trying to debug two plugins that I am developing. As background info: I have a PHP call to strip_tags() that allows user defined HTML tags. When the tag <li> is stripped I get multiple action/filter callbacks to my plugins. When the <li>tag is NOT stripped the multiple action/filter callbacks stop. Very weird! Something may be getting corrupted. I would like to know which action/filter is currently active to help in debugging.