2006-09-25
Detainment Spell prevents mana abilities of the enchanted creature from being activated.
2006-09-25
Morph isn't an activated ability, so Detainment Spell doesn't prevent face-down creatures from being able to turn face up.
2006-09-25
Responding to a creature's activated ability being activated by moving Detainment Spell onto that creature won't affect the ability that was just activated.