# File lib/sup/modes/inbox-mode.rb, line 33
  def archive
    return unless cursor_thread
    thread = cursor_thread # to make sure lambda only knows about 'old' cursor_thread

    UndoManager.register "archiving thread" do
      thread.apply_label :inbox
      add_or_unhide thread.first
      Index.save_thread thread
    end

    cursor_thread.remove_label :inbox
    hide_thread cursor_thread
    regen_text
    Index.save_thread thread
  end