I have a simple setup at the moment which is 1 monitor ontop of another and i can't get mutliplicity pro to work right.. i upgrade from standard specifically for the up/down switching and it is still working left to right when i setup the grid... when i go into advanced and check the stacked vertical checkbox it sort of works except it treats my primary as if its on top not the bottom!! So it backwards... I also prefer not to use this checkbox since eventually i'll also have left and right monitors.