end
  if State.cursor1.pos == nil then
    State.cursor1.pos = 1
  end
  -- hack: insert a text line at bottom of file if necessary
  if State.cursor1.line > #State.lines then
    assert(State.cursor1.line == #State.lines+1)
    table.insert(State.lines, {mode='text', data=''})
    table.insert(State.line_cache, {})
  end
--?   print(y, App.screen.height, App.screen.height-State.line_height)
  if y > App.screen.height - State.line_height then
  State.screen_top1 = {line=State.screen_bottom1.line, pos=State.screen_bottom1.pos}
--?   print('setting top to', State.screen_top1.line, State.screen_top1.pos)