[Shotwell] crop_tool_window layout changes when selecting "Custom" cropping

[Paul Novak]

Hello,

I have built shotwell from SVN on Fedora 12. When I use the crop tool,
and select the "Custom" crop constraint, the layout of the crop tool
window changes so the "Cancel" and "OK" buttons are on the left. This
layout persists when I change to any other crop constraint. I think this
happens because the tool window layout is initialized by (from
EditingTools.vala)

            Gtk.HBox response_layout = new Gtk.HBox(true, CONTROL_SPACING);
            response_layout.add(cancel_button);
            response_layout.add(ok_button);

            layout = new Gtk.HBox(false, CONTROL_SPACING);
            layout.add(constraint_combo);
            layout.add(pivot_reticle_button);
            layout.add(response_layout);

but when the constraint type changes, response_layout is not removed,
just its children, cancel_button and the ok_button. I'm not sure how to
fix it, because I don't know how to access response_layout to remove its
children first (cancel_button and ok_button), and then remove
response_layout.

I'd be glad to create the patch if someone pointed me in the right
direction.

Thanks,
Paul