sundry CAPI questions

Hello,

I have been using graph-pane in a variety of ways because of its
capabilities for tree graphing.  Some things are not documented, to wit:

Collapsing nodes - I found graph-layout-collapse-node and
graph-layout-expand-node and the node-state-table on the graph-layout which
gets populated with entries (<node> :collapsed) when a node is collapsed.
Are there additional mechanisms (methods, funtions) controlling the
appearance of collapsed nodes or does one simply do a hashtable lookup in
the draw-pinboard-object method and modify rendering there?

I am displaying directed cyclic graphs rather than trees.  I prevent
cycling in the display by use of directedness, but CAPI's depth first
strategy when laying out the tree makes the graphs ugly.  Any way of
modifying the strategy to breadth-first, short of rewriting the tree-graph
display methods?

And if not, what are the redraw callback methods that are invoked from the
window system when a window is (i.e.) unobscured?  In other words, what
methods should I provide so that the pane draws and refreshes properly?

TIA

Raymond Laning