Layering gnome canvas items properly

[The Surprises <thesurprises1 attbi com>]

I am building a GUI in which I am trying to layer canvas items on top of
each other.  For example, I have a base rectangle.  On top of the base
rectangle, I want to draw a line, and on top of the line, I want to draw
some rectangles.  I've been trying to use the
gnome_canvas_item_{lower,raise,lower_to_bottom,raise_to_top} methods but
I can't seem to get it right.  Sometimes it looks right, sometimes it
messes up after a redraw.  I don't get it.  Has anyone been able to
layer canvas items correctly?

Thanks,
Jason