panel —
z-order for curses windows
Z-order for curses windows (libpanel, -lpanel)
Overlapping curses windows have no notion of z-order, what you see on the screen
  depends on the order of updates. The panel library is
  an extension built on top of
  curses(3) that adds z-order to
  curses windows.
Each panel has an associated curses window. All currently visible
    panels form a “deck”. Panels have z-order only relative to
    other panels in the deck and to stdscr. The latter doesn't have a panel of
    its own but implicitly lies below all other panels in the deck. If you mix
    plain curses windows and panels, the visual results are undefined since the
    panel library is not aware of windows that are not associated with
  panels.