end
-- titles are optional and so affect the height of the pane
function add_title(pane, title)
  pane.title = title
  pane._height = nil

function should_update_screen_top(column_index, pane_index, pane, options)
  if column_index ~= Cursor_pane.col then return true end
  if pane_index ~= Cursor_pane.row then return true end
  -- update the cursor pane either if it's not editable, or
  -- if it was explicitly requested
  if not pane.editable then return true end
  if options == nil then return true end
  if not options.ignore_editable_cursor_pane then return true end
  if not Editable_cursor_pane_updated_screen_top then return true end
  return false

-- titles are optional and so affect the height of the pane
function add_title(pane, title)
  pane.title = title
  pane._height = nil

end
function should_show_column(sx)
  return overlap(sx-Margin_left, sx+Display_settings.column_width+Margin_right, Display_settings.x, Display_settings.x + App.screen.width)

function should_show_pane(pane, sy)
  return overlap(sy, sy + Margin_above + height(pane) + Margin_below, Display_settings.y, Display_settings.y + App.screen.height - Header_height)

function should_update_screen_top(column_index, pane_index, pane, options)
  if column_index ~= Cursor_pane.col then return true end
  if pane_index ~= Cursor_pane.row then return true end
  -- update the cursor pane either if it's not editable, or
  -- if it was explicitly requested
  if not pane.editable then return true end
  if options == nil then return true end
  if not options.ignore_editable_cursor_pane then return true end
  if not Editable_cursor_pane_updated_screen_top then return true end
  return false

function should_show_column(sx)
  return overlap(sx-Margin_left, sx+Display_settings.column_width+Margin_right, Display_settings.x, Display_settings.x + App.screen.width)
end
function should_show_pane(pane, sy)
  return overlap(sy, sy + Margin_above + height(pane) + Margin_below, Display_settings.y, Display_settings.y + App.screen.height - Header_height)
end