Maybe this is a new mode option for front defog... or maybe they've changed it so it works sensibly!
I didn't get much winter experience, but I did start to get front and side fogging on a couple of those cold and damp days we still had in early March after I got my car. What I did was manually select Front Defrost + Floor, set the temperature to a comfortable level and turned the fan up to at least 8. That worked to keep the windshield and most of the side window clear. Now again, this wasn't the depths of winter, so I'm hoping the vent re-design (which I haven't got yet) and these software tricks in 4.5 will do the trick.