How to copy when you use vnc under the Ubuntu

* My requirment:
  I use vnc-client in the Ubuntu 12.04 to connect the lab which was the RH el5,
  But I found that, I cannot copy from the app in the client to the server.

  how to show the version of your system:
  # cat /proc/version to show the version.
  # lsb_release -a

  So I try to find the reason and learn something else:
  about X:
 
  http://blog.chinaunix.net/uid-24701781-id-3541147.html
 
  about GNOME & KDE:
 
  about X-term, GNOME Terminal..:

  about clipbord in the X windows system:
 
  http://blog.chinaunix.net/uid-24701781-id-3541152.html


* solution
 
  this guy had done lots of work to meet our common needs.

  http://blog.csdn.net/hongqun/article/details/6222895

  but I found a simple solution:
 
  I just seach in the Ubuntu software store.
  and find an app which is called "SSL/SSH/VNC Viewer".
  It seems that this app had supported this feature.