id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
16992	Comments - no custom columns hook	stencil		"There is a do_action('manage_comments_custom_column') in:[[BR]]
wp-admin/includes/class-wp-comments-list-table.php (Line 503)

But no hook to filter the columns of the Comments table.

Small possible fix attached which applies filter.
"	defect (bug)	closed	normal		Comments	3.1	normal	worksforme