def _convert_index_to_printable_row index=@current_index
      r,c = rowcol
      pos = _convert_index_to_visible_row(index)
      return nil unless pos
      pos = r + pos
      return pos
    end
def _convert_index_to_printable_row index=@current_index
      r,c = rowcol
      pos = _convert_index_to_visible_row(index)
      return nil unless pos
      pos = r + pos
      return pos
    end
actual position to write on window
 NOTE can return nil, if user scrolls forward or backward