substack and systemWindow property

[Ops]

I have a mainstack and 1 substack.  In a mouseEnter handler of a field 
in the mainstack I "show" the substack.  So far so good...however, when 
the mainstack's systemWindow property is true, and it is floating above, 
say, a full-screen browser window, moving the mouse in the field that 
"shows" the substack on mouseEnter does not make the substack visible 
(even though the substack's "vis" and "systemWindow" properties are both 
true).  Obviously, the substack is in fact "popping up", but is not 
visible because it is *behind* the browser window.  Any ideas on what I 
can do to make that darn substack show visible above the (in this 
example) browser window??

Thanks!!

Opie