I'm curious to know how Mac handles apps moving between a Retina Display Mac and a non-Retina display (Thunderbolt, whatever). Apps need to be updated to handle retina, otherwise they draw double pixels.. so what happens when you have a window that's halfway between a Retina and non-Retina?

My two guesses: 1. The entire window draws as doubled pixels, as if it didn't support Retina at all 2. The window gets two separate paint events, one retina and one non-retina.

Anyone know how this works yet?