Would like to tell me how to show history line in picture?

list Tang Yong
Sun, 22 Jun 2008 21:22:31 +0800
Message-Id: <00c101c8d473$e3254fe0$0201a8c0@sundia001>

Hello!
   Hobbit is a good tool software for monitoring servers, applications and networks, very much!
   Would like to tell me how to show history line in picture?
   Thank You very much!

Tang Yong
2008-06-22