Strike out topic title on lock
When the topic is locked, it will show up in viewforum with it's title strike out.
Open
viewforum.php
FIND:
$folder = ($user_replied && defined('USER_REPLIED_ICON')) ? $images['folder_locked_own'] : $images['folder_locked'];
AFTER ADD
$topic_title = "<strike>" . $topic_title . "</strike>";