Auto-scrolling the scrollbar on a TreeView

[Rob Hoelz <hoelz wisc edu>]

Hello everyone,

I'm currently using a Gtk2 TreeView within a Gtk2 ScrolledWindow, and
I'd like to be able to navigate the tree using the keyboard.  I've set
up key bindings so Right expands a tree, Left collapses it, and Up and
Down seem to be already set to navigate expanded cells.  However, when
I use Down to navigate to a cell off-screen, I'd like the
ScrolledWindow to compensate.  I've tried scroll_to_cell, but to no
avail.  Any hints?  I've posted the source code at
http://cs.wisc.edu/~hoelz/TodoList.pl; the problem is in the callback
at line 157.

Thanks,
Rob Hoelz