Minerva and Appropriate

[RaidingPig]

So basically I was playing a duel the other day, and I activated Minerva, The Exalted Lightsworn's effect. My opponent said "ok". I then milled 3 cards, including a Lightsworn monster, so I proceeded to draw 1 card. My opponent said "chain to draw" and activated Appropriate.
He can't activate a card while another effect is resolving, right?

[Zaziuma]

Well no, but he is technically able to activate the card in this situation, but saying he is Chaining to the draw was him using incorrect wording. Rather, he activates the card after the Chain resolved, which is the timing Appropriate can be activated. It's an odd card, since at that point, he actually isn't even able to draw anything from it, that is only its activation condition, only new triggers would allow him to draw.

[RaidingPig]

Yeah that guy chained another appropriate and tried to draw 4
That's why I was kinda confused. Thank you for explaining it to me...

[Zaziuma]

Well, then he's a cheating bastard.