# File lib/sup/modes/thread-index-mode.rb, line 357
  def toggle_archived 
    t = cursor_thread or return
    undo = actually_toggle_archived t
    UndoManager.register "deleting/undeleting thread #{t.first.id}", undo, lambda { update_text_for_line curpos },
                         lambda { Index.save_thread t }
    update_text_for_line curpos
    Index.save_thread t
  end