You can iconify an interface window as follows:
(setf (top-level-interface-display-state interface) :iconic)
You can also make it be hidden, maximized or restore it to normal, and you have the option to create it in one of these states initally. For details see the documentation for
top-level-interface-display-state
in the
LispWorks CAPI Reference Manual
.
CAPI User Guide (Macintosh version) - 30 Aug 2011