Thoughts? Should we remove these gtkmm-specific
Box::pack_start()/pack_end() methods anyway? That will still have the
same change-of-behaviour problem for this code:
box.pack_start(child)
but if an application also has code like this it will at least cause a
compiler error that forces the developer to think about it:
box.pack_start(child, Gtk::PACK_SHRINK).
Why does Gtk::PackOptions affect only horizontal expansion and
alignment? Look for instance at one of the 3 TreeView demo
programs. The ScrolledWindow is expanded horizontally but not
vertically. Before the expand and fill parameters were removed from
gtk_box_pack_start() the ScrolledWindow was expanded in both
directions.