I am having the same problem. I also have posted about this,
but have not recevied any answer.
I am doing a manual screen shot when I am done scrolling or
doing a drag and drop action. I copy the background from the manual
screen shot, then paste it as the background on the incorrect
slide. It is annoying, but I have done half my demos in 2 and half
in 3, so I am stuck with 3.