-- Delete any columns dedicated to just this note, and update cursor pane if necessary.
  local delete_cursor_column = Surface[Cursor_pane.col].name == pane.id
  for i=#Surface,Cursor_pane.col+1,-1 do
    local column = Surface[i]
    if column.name == pane.id then
      table.remove(Surface, i)
    end
  end
  local num_deleted = 0
  for i=Cursor_pane.col,1,-1 do
    local column = Surface[i]
    if column.name == pane.id then
      table.remove(Surface, i)
      num_deleted = num_deleted+1
    end
  end
  if num_deleted > 0 then
    Cursor_pane.col = Cursor_pane.col - num_deleted
    if delete_cursor_column then
      Cursor_pane.row = 1
    end
  else
    assert(not delete_cursor_column)
  end