The current SD multiple monitor "implementation" does leave much to be desired.... not sure why it was set where the 2nd monitor has to be a touchscreen?! Only thing I can think of is that it was does this way at the recommendation of a lawyer....

Here's hoping useful multi-monitor support in high on the dev team's list of features!

In the mean time, I'd recommend checking out Centrafuse. It's multi-monitor implementation is near perfect (AV source configurable by media type). They are even adding gesture support shortly... Sadly, despite a well thought-out/implemented feature list, I find the Centrafuse user interface far too clunky and counter-intuitive to be useful in a car environment. I'll be sticking by StreetDeck for a while longer, despite this obvious flaw. : )