Path: utzoo!attcan!uunet!ncrlnk!ncr-sd!hp-sdd!hplabs!ucbvax!bloom-beacon!EXPO.LCS.MIT.EDU!rws
From: rws@EXPO.LCS.MIT.EDU (Bob Scheifler)
Newsgroups: comp.windows.x
Subject: Re: Finding which windows are under cursor
Message-ID: <8812071254.AA12153@EXPO.LCS.MIT.EDU>
Date: 7 Dec 88 12:54:34 GMT
References: <2178@vedge.UUCP>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 6


    The problem is that I need to find the stacking order of the windows
    directly under the cursor; neither XQueryTree or XGetGeometry help.

Wrong.  QueryTree does provide sufficient stacking order information.
Go read your Xlib and Protocol manuals again.