Creating a custom composite widget: StackedTreeView

["Darren Hart" <darren dvhart com>]

I'm looking to write a custom widget which I call a StackedTreeView.
It's basically a TreeView with multiple models, each one having a
button to update the view to use its model.  I'd build this out of
individual widgets by making an hbox with one cell for the view and
one cell per model for the buttons.  When the user presses a button
the treeview is moved to the cell just below the button pressed and is
assigned the button's corresponding model.

So, does it make sense to just write a Mediator that wrapps an hbox
with all these things, or does it make sense to write my own widget.
If I were to write my own widget, do I derive from TreeView?  If so,
how do I add buttons, and what handles the packing?

Is there some best-practices document or something regarding creating
composite widgets with gtk?

-- 
Darren Hart