Need window that always stays at the back

[joofung@iss.nus.sg (Wong Joo Fung)]

Hi:

I have created a desktop window (similiar to the Finder's desktop) in my
application.  Clicking on an object on the desktop opens a display window to
reveal the object's contents.

Is there a way to keep the desktop window in the back at all times, even if
all the display windows in front of it are inactive?  That is, clicking on the
desktop window will activate it (and deactivate the frontmost display window)
but will not bring the desktop window to the front.

(Yes, I know that this is not how Macintosh windows usually work -- but I need
to mimic the functionality of the Finder's desktop.  Perhaps it's possible to
override the WINDOW-SELECT and WINDOW-SELECT-EVENT-HANDLER to get the desired
effect).

Any pointers would be much appreciated.

Thank you,
JooFung Wong