Q: Xserver / Composite behavior

[Amir Bukhari]

What happend when application move it's top level window out side root
window. Example: screen is 1200x1024 and a window is moved to 1600,512 which
out side screen. Does Xserver will not alow it or it will only not be
visable?
does Xcomposite will stil render to off-screen pixmap?

Answer for this will solve alot of calculation I do on my side to support
multiscreen enviroment in LG!

-Amir