I'm testing a TMSFNCGrid. It seems that the behavior of the scrolling it's the same regardless of the value of ScrollMode.
I assume that the scmItemScrolling value will scroll full rows vertically and full columns horizontally, however, it does not do this. Does the same as with the scmPixelScrolling value. Maybe it's a bug.
I tried with TMSFMXGrid with similar values in Options.Mouse.*Scrolling and with smCellScrolling value in ScrollMode and it works as expected.
TIA,
Ricardo