When watching films the screen drifts, very, very slowly but enough to be really annoying, it can end up 180 degrees from where it started playing.

I like the program but this problem is enough to make me use an alternative. I like to lie in bed and watch but as you can imagine, if the screen drifts sideways, it becomes uncomfortable to have to move around in order to see the screen. The screens position is adjustable up and down and zooming in and out but not sideways? Just that adjustment alone would help. Even better, make it more stable and get it to stay in one place.