This is interesting because I have direct experience with this on real hardware recently. I have a GeForce 4 MX440 graphics card connected via DVI to a native 1920x1200 display. Windows 98 will let me set the native resolution, but if I move the mouse outside the bounds (maybe 1152x864?) the whole screen will "pan" with the cursor and wrap to the other side of the screen. It's almost like 98 can display 1920x1200 but can only interact with a subset of it. I thought it was just some strange driver limit or an issue with my hardware, but maybe it's a limit in the core of the OS.