--?   print('top1 finally:', State.screen_top1.line, State.screen_top1.pos)

      -- make sure cursor remains in view (particularly so we can continue undoing)
      if Text.cursor_out_of_screen(State) then
        if Text.lt1(screen_top_before, State.screen_top1) then
          bring_cursor_of_cursor_pane_in_view('down')
        else
          bring_cursor_of_cursor_pane_in_view('up')
        end
      end