[gtk+970606] problems with gtk_widget_destroy()

[David Mosberger-Tang <davidm azstarnet com>]

gtk+970606 breaks the rebuilding of the device-specific user-interface
in SANE (e.g., enabling the gamma curves and then disabling them again
does _not_ make the curve widget disappear).

Unfortunately, I don't have much time to track this down. It looks
like inserting a vbox into an hbox via a gtk_container_add()
increments the ref count in the vbox by two.  So a gtk_destroy() on
the vbox does not (fully?) destroy that box and its contents.  Some of
the things in the vbox do disappear as a result of the gtk_destroy(),
but it looks like widgets that are two or more levels inside the vbox
remain (judging based on the _looks_ alone).  Maybe what's really
happening is that the widgets inside a vbox that don't have their own
window get cleared off the screen while widgets with windows remain
(the widgets that get cleared are labels and frames).

The same code used to work fine with earlier versions of gtk.  Anybody
has an idea how this needs to be fixed?

	--david