thanks !
i follow the artcle you mention :
disable compositing with Option “Composite” “Disable” and restart your X server,applications now not freeze any longer
i think is the compositing problems
then Put it in the device section of my xorg.conf: Option “UseCompositeWrapper” “true” and enable compositing again,
restart my x server.
it seems the solution dose not work in my computer!
what can i do about the problem??
thanks