Checks if a given spell ID has an active spell overlay. This function continues to return expected results even if the user has spell overlays disabled, and is used internally to check if an action button should display a glow. This function does not work with macro ID's.
See also Spell functions, Action functions.
Signature:
state = IsSpellOverlayed(spellID)
Arguments:
spellID- The ID of the spell to check. (integer, spellID)
Returns:
state- 1 if the passed spell ID has an associated spell overlay active, nil otherwise. (boolean)