A little bit of rules lawyering:
The rules say that:
a) Stunned heroes can't use their constant powers.
b) A hero may use its constant power at any point during the player's turn, but not after the player has drawn power.
Do you see the controversy?
Let's say that Disco Droid is stunned, so it can't use Disco Fever... right until after phase 3 when it is un-stunned. The player has not drawn power yet so Disco Droid gets to attack!
This way constant powers are rendered effectively immune to stun in most cases. Is that meant to be so or is it just a point that needs to be clarified a bit?
Point A is meant to imply "... for the entire turn" and point B is meant to imply "on a turn when the hero is not stunned..." But technically I do see the loophole! But yes, if a hero is stunned it cannot use any powers at all on that turn, including constant powers.