Our fastback does the same thing, open a door and window goes down slightly, we had our windows tinted, and had this done through Ford, so its covered under factory warranty for this reason, after installation of tint, sticker inside car says don't put windows down for 48 hours, yeah try telling that to the car, as it does it by itself.
Hopefully we wont need the factory warranty, but it gives peace of mind for the additional cost over any other window tinter.
Cheers
Keith