fpSpread1.DialogKey += FpSpread1_DialogKey;

private void FpSpread1_DialogKey(object sender, FarPoint.Win.Spread.DialogKeyEventArgs e)
{
    if(e.KeyCode == Keys.Enter)
    {
        if(fpSpread1.ActiveSheet.ActiveColumnIndex == 0)
        {
            fpSpread1.ActiveSheet.SetActiveCell(fpSpread1.ActiveSheet.ActiveRowIndex, 5);
            e.Handled = true;
        }
    }
}

fpSpread1.EditModeOff += FpSpread1_EditModeOff;

private void FpSpread1_EditModeOff(object sender, EventArgs e)
{
    if (fpSpread1.ActiveSheet.ActiveCell.Value != null)
    {
        MessageBox.Show("FpSpread1_EditModeOff");
    }
}