iOS Simulator scaling on a retina display
If the iOS Simulator scaling is set to 75% or 100% on a non-retina display, scale it to 50% before moving it to a retina display.
One of the biggest advantages of a Retina MacBook Pro is that the iOS Simulator can run at 100% resolution and you get a good feel for what your app will look like on the real device. Running the simulator on an external display, you often need to scale down the window to 75% or 50% in order to view the whole thing.
If the simulator scaling is set to 100% or 75% on a non-retina display, it will retain its seemingly large size when moved to the retina display.
Before moving the simulator to a retina display, set the scaling to 50%. The simulator will detect the retina display and set its scaling to 100%.
Exactly as we want.
The iOS Simulator only seems to auto scale if its scaling is set to 50% on a non-retina display.