# File lib/sup/modes/thread-view-mode.rb, line 442
  def jump_to_prev_open
    m = (0 .. curpos).to_a.reverse.argfind { |i| @message_lines[i] } # bah, .to_a
    return unless m
    ## jump to the top of the current message if we're in the body;
    ## otherwise, to the previous message
    
    top = @layout[m].top
    if curpos == top
      while(prevm = @layout[m].prev)
        break if @layout[prevm].state != :closed
        m = prevm
      end
      jump_to_message prevm if prevm
    else
      jump_to_message m
    end
  end