Hey FOURWHL,
I had the same issue with the window in the forward Bunk, a blue DX3 flew by at 80+mph on the Interstate Hwy70 in Co. and my window flew open.
You wouldn't know who that might be would you ?
It had happened on my way home from TX as well. The screws holding the Knob(s) were loose on more than half the widows, you're going to have to check them all. On the sticky ones, I used armor all on the rubber and that did the trick.