i suppose your laptop has two video cards, a low-power video card and a hight power NVIDIA/ATI graphics card.
Switching between low-power and high-power video cards is the most likely culprit. To confirm, disable one of the video cards, and see if the problem goes away.
It may even be more of a problem for TouchScreens because they have to maintain two calibrations, one for each card.
i suppose your laptop has two video cards, a low-power video card and a hight power NVIDIA/ATI graphics card.
Switching between low-power and high-power video cards is the most likely culprit. To confirm, disable one of the video cards, and see if the problem goes away.
It may even be more of a problem for TouchScreens because they have to maintain two calibrations, one for each card.