Quote Originally Posted by Doo View Post
No idea but tanks need to rotate targets to build hate on the adds so it might not be the one you want to attack.
Pretty sure it only appears when the tank's locked target changes. If you're cycle tabbing through targets to, say, use Halone once and return to the primary target, it doesn't appear. I don't have access to the game right now, but I'll have to look more carefully next dungeon I run.