What SugarCRM version are you using? I only have a pro version here. Look for the following line on EditView2.php file under include/EditView directory. $this->th->ss->assign('fields', $this->fieldDefs);
It is not advisable to modify core codes on sugarcrm. You might as well create a custom view.detail.php file custom/Leads/ directory. I assume you are new to sugar and the following link would be very helpful to you. http://archive.h2ik.co/2012/03/sugarcrm-upgrade-safe-way-to-extend-views/