Multiple times now, I've had a game-winning card in hand after my opponent has milled my library to the point it is empty. I've been too slow, apparently, at setting a stop after the milling and have subsequently lost on the following draw step.

I'd like to ask that a stop be placed automatically on any empty library upkeep step, or at least when there is an instant in hand that can be cast. It's disappointing that, were this paper magic, I'd be able to respond and win the game.

I've attached a screenshot of the game that just ended where this happened. Opponent has 4 life remaining and I have a Burst Lightning in hand with more than five available mana to cast the spell on upkeep.

Thanks