The free layout mode arranges the child nodes of each
node starting recursively from the root so that the links flow roughly
in the same direction. For instance, if the link flow direction is
top-down, the root node is placed at the top of the drawing. Siblings
(nodes that have the same parent) are justified at their top borders,
but nodes of different tree branches (nodes with different parents)
are not justified.
To set the free layout mode:
treeLayout.setLayoutMode(ibm_ilog.graphlayout.tree.TreeLayout.FREE);