Hearthpwn

I noticed that this doesn't trigger in many circumstances. Enemy players spells don't trigger (like fireball or frost shock). Enemy hero attacks don't trigger this either. Other secrets like counter spell (if i cast pyroblast at the other mage and they have counter spell, it doesn't trigger ice barrier when i'm hit). also minion battlecry's like nightshade battlecry 3 damage to enemy hero. seems only direct attack from minions triggers this.