Description of problem:
While the network broken between the VNC server and the VNC client, the VNC server's X11 desktop froze under the condition of big amount of screen fresh/delta. 

Version-Release number of selected component (if applicable):
RealVNC free edition 4.0, vnc.so 

How reproducible:


Steps to Reproduce:
1. Establish a VNC session between a VNC server and a VNC client. 
2. Open a xterm on the VNC server, 
   then enlarge the opened xterm window as large as possible
3. In the opened xterm window:
   login as user 'root'                      : $ su -
   execute command to let screen keep update : # ls -l /
4. Pull off network cable from the VNC client.   
  
Actual results:
The VNC Server window froze immediately or keep updating for a short period then window froze.

Expected results:
The VNC Server window should keep updating, no matter the client session was broken or not.  

Additional info: