id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
10595	Allow plugins to add columns to user management screen	martinv5		"It's here on line '''1974''' in wp-admin/includes/template.php:

apply_filters('manage_users_custom_column', '', $column_name, $user_object->ID);

An '''empty argument''' it passed to the filter instead of the actual column name.

See the file here http://core.trac.wordpress.org/browser/branches/2.8/wp-admin/includes/template.php 

Or am I missing something?

Thanks,
M."	feature request	closed	high		Administration	2.8.3	trivial	duplicate	manage_users_custom_column user management