Minor issue: Supply the following four definitions. | SWM

=> pane-viewport pane [Generic Function]
=> pane-viewport-region pane [Generic Function]
=> pane-scroller pane [Generic Function]
=> scroll-extent pane x y [Generic Function]
=> label-pane [Service Pane]
=> labelled (&rest options) &body contents [Macro]
Creates a pane that consists of the specified label, which is a string.

29.3.4 The Layout Protocol

The layout protocol is triggered by layout-frame, which is called when a frame is adopted by
a frame manager.

CLIM uses a two pass algorithm to lay out a pane hierarchy. In the first pass (called called
space composition), the top-level pane is asked how much space it requires. This may in turn
lead to same the question being asked recursively of all the panes in the hierarchy, with the
answers being composed to produce the top-level pane's answer. Each pane answers the query
by returning a space requirement (or space-requirement) object, which specifies the pane's
desired width and height as well as its willingness to shrink or grow along its width and height.