Backing store issue in FC12

[vinod gullu]

  Dear All,
  
  I have installed FC12 64 bit on my  PC. When i am
  longing into remote PC and trying to open the graphics
  applications on remote PC, The window becomes black .
  
  I have put Option "Backingstore" "on" in my xorg.conf in
  Device section. 
  
   But now the moment I log into remoter M/C and launch
 the  graphics application on remote M/C, The system logs out
 from  remote as well as local M/C.

If i remove the backingstore option, the remote graphics works, but window becomes black, if moved here and three.
  
  Any diagnosis for this?
  
  Thanks in advance
  
  
  VINOD KUMAR GULERIA ADD/AERO VSSC, TRIVANDRUMKERLA-
 695022
  0471-2564429,2564938(OFFICE)+91 9447109608 (RES)