Switching Desktops: applications move unexpectedly

[Joe Riel]

I like to start applications in specific desktops:
a mail reader in one, a browser in another, etc., and then
switch to that desktop to use that application.  
Alas, if one application calls another, say I click a URL in
an email to open the link in the browser, rather than
taking me to the desktop where the application [browser]
is located, the application is moved to the current desktop.

Is there a way to change this behavior?  I'd prefer that
applications stay in their assigned desktop.

-- 
Joe Riel