problem gdk_window_lookup function

["Saripalli Siva Prakash venkata phani" <svp siva gmail com>]

Hi,
Im trying to write a application.
I called gdk_window_lookup with a valid xid to get a GdkWindow structure...
But the function just returns NULL.
Can anybody tell me what mistake i cud have made?
and im using gnome only on my fedora core 6 system..

-- 
Saripalli Siva Prakash V P
Junior Year, BTech
CS04B024
Computer Science and Engineering
IIT MADRAS
Mobile No:- 09246626159

http://www.cse.iitm.ac.in/~svpsiva