Modifying Member search function


I am having a slight issue with the search function of the administrative menu for "All Members". I am trying to make the search also look for a user display_name, which is currently not working for me.

I looked into the code and saw that there is a piece for display_name on line 159 of class.membersearch.php. It looks like it should be placed in the array above, however (line 155 & 157)

I was wondering if anyone has heard of this issue before?

Thank you