How to redefine button functionality on a GtkTree?

["Steven J. Hill" <sjhill plutonium net>]

I am trying to capture button press events within a GtkTree. However, I
notice that if I press the middle mouse button on a GtkTreeItem that has a
subtree
and is collapsed, it expands the subtree. And if I press the right mouse button,
it
collapses the subtree. How do I redefine what those events do and how do I parse
the events to see if the middle or right button was pressed? I looked at the
'gtk_widget_set_events' method, but I am not quite sure how to make things work
yet. Thanks in advance.

-Steve