code: def list_panes(pymux, variables):
      
      w = pymux.arrangement.get_active_window()
      active_pane = w.active_pane
  
      result = []
  
      for i, p in enumerate(w.panes):
          process = p.process
  
          result.append('%i: [%sx%s] [history %s/%s] %s' % (
              i, process.sx, process.sy,
              min(pymux.history_limit, process.screen.line_offset + process.sy),
              pymux.history_limit,
              ('(active)' if p == active_pane else '')))
  
      # Display help in pane.
      result = '\n'.join(sorted(result))
      pymux.get_client_state().layout_manager.display_popup('list-keys', result)
docs: Display a list of all the panes.