When running in horizontal span (5120x1600) the menus are offset by about 70% up (tab as well as other popup menus). This goes away when running in dual view mode and treating each display as 2560x1600.
H8 works fine in both modes.

Red dot is where the mouse cursor is in the image.

h9 9.0.741
winxp
gf 8800gtx 163.71