When you first start the Interface Builder, a new interface is created for you automatically. You can also choose File > New or click on to create a new interface. A blank window, known as the interface skeleton , appears on-screen, as shown in Skeleton window. The interface skeleton contains no layouts or panes, or menus.
Figure 19.2 Skeleton window
You can use File > New to create as many interfaces as you want; they are all displayed as soon as you create them. Since you can only work on one interface at a time, use the History > Items submenu or the and toolbar buttons to switch between different interfaces that are currently loaded in the Interface Builder.
As an alternative, type the name of an interface directly into the Interface text box and press
to create a new interface, or to switch to an interface which is already loaded.
LispWorks IDE User Guide (Unix version) - 25 Nov 2011