ok, here are my computer specs:
i have a laptop: msi cx600 with a widescreen monitor. my rezollution is 1366x768 and i don't think it is a multicolor system. It runs on windows 7 ultimate final build: 7600 and on a clean desktop (with no gadget enhancements or anything) . I also have windows aero enabled, but that is not the problem.
by moving to another fence i really mean move to another fence not to another spot on the screen. sometimes it moves into a fence bellow the visible area of it adding a scrollbar to that particular fence so i simpli cannot see it anywhere on my screen so i have to click an icon and click the initial of that icon's name untill it focuses on it in order to find it.
it seems to happen sometimes regardless the game i use, but tipically i think as a pattern it happens when i enter a game which has a resolution ratio different from my screen's (for example i enter nsf most wanted that has a 4:3 rez and my laptop has 16:9. the game does not stretches, instead it is centered on my screen and black space is added at either sides.) Each and every time i run that game it moves to a different fence( yes, sometimes it moves on a different part of the desktop as well)
i will happily provide you with more info if you need and if you still don't manage to reproduce it i can give you a live view of my desktop and show it to you from my computer.
Glad to be of service,