Incompatible Changes from GTK+-1.2 to GTK+-1.4:

* The gdk_time* functions have been removed. This functionality
  has been unused since the main loop was moved into GLib
  prior to 1.2. 

* The signature for GtkPrintFunc (used for gtk_item_factory_dump_items)
  has been changed to take a 'const gchar *' instead of 'gchar *', to
  match what we do for glib, and other similar cases.

* The detail arguments in the GtkStyleClass structure are now 'const gchar *'.

* gtk_paned_set_gutter_size() has been removed, since the small handle tab
  has been changed to include the entire area previously occupied by
  the gutter.

* GDK no longer selects OwnerGrabButtonMask for button presses. This means  
  that the automatic grab that occurs when the user presses a button
  will have owner_events = FALSE, so all events are redirected to the
  grab window, even events that would normally go to  other windows of the
  window's owner.

* GtkColorSelectionDialog has now been moved into it's own set of files,
  gtkcolorseldialog.c and gtkcolorseldialog.h.

* gtk_widget_shape_combine_mask() now keeps a reference count on the 
  mask pixmap that is passed in.

* Type system changes:
  - GTK_TYPE_OBJECT is not a fundamental type anymore. Type checks of the
    style (GTK_FUNDAMENTAL_TYPE (some_type) == GTK_TYPE_OBJECT)
    will not work anymore. As a replacement, (GTK_TYPE_IS_OBJECT (some_type))
    can be used now.
  - The following types vanished: GTK_TYPE_ARGS, GTK_TYPE_CALLBACK,
    GTK_TYPE_C_CALLBACK, GTK_TYPE_FOREIGN. The corresponding GtkArg
    fields and field access macros are also gone.
  - The following type aliases vanished: GTK_TYPE_FLAT_FIRST,
    GTK_TYPE_FLAT_LAST, GTK_TYPE_STRUCTURED_FIRST, GTK_TYPE_STRUCTURED_LAST.
  - The type macros GTK_TYPE_MAKE() and GTK_TYPE_SEQNO() vanished, use of
    GTK_FUNDAMENTAL_TYPE() is discouraged. Instead, the corresponding GType
    API should be used: G_TYPE_FUNDAMENTAL(), G_TYPE_DERIVE_ID(),
    G_TYPE_BRANCH_SEQNO(). Note that the GLib type system doesn't build new
    type ids based on a global incremental sequential number anymore, but
    numbers new type ids sequentially per fundamental type branch.
  - The following type functions vanished/were replaced:
    Old Function		 Replacement
    gtk_type_query()		 - being investigated -
    gtk_type_set_varargs_type()	 -
    gtk_type_get_varargs_type()	 -
    gtk_type_check_object_cast() g_type_check_instance_cast()
    gtk_type_check_class_cast()	 g_type_check_class_cast()
    gtk_type_describe_tree()	 -
    gtk_type_describe_heritage() -
    gtk_type_free()		 -
    gtk_type_children_types()	 g_type_children()
    gtk_type_set_chunk_alloc()	 GTypeInfo.n_preallocs
    gtk_type_register_enum()	 g_enum_register_static()
    gtk_type_register_flags()	 g_flags_register_static()
    gtk_type_parent_class()	 g_type_parent() / g_type_class_peek_parent()
    Use of g_type_class_ref() / g_type_class_unref() and g_type_class_peek()
    is recommended over usage of gtk_type_class().
    Use of g_type_register_static() / g_type_register_dynamic() is recommended
    over usage of gtk_type_unique().

* Object system changes:
  GtkObject derives from GObject, so is not the basic object type anymore.
  This imposes the following source incompatible changes:
  - GtkObject has no klass field anymore, an object's class can be retrived
    with the object's coresponding GTK_<OBJECT>_GET_CLASS (object) macro.
  - GtkObjectClass has no type field anymore, a class's type can be retrived
    with the GTK_CLASS_TYPE (class) macro.
  - GtkObjectClass does not introduce the finalize() and shutdown() methods
    anymore. While shutdown() is intended for GTK+ internal use only, finalize()
    is required by a variety of object implementations. GObjectClass.finalize
    should be overriden here, e.g.:
    static void gtk_label_finalize (GObject *gobject)
    {
      GtkLabel *label = GTK_LABEL (gobject);
      
      G_OBJECT_CLASS (parent_class)->finalize (object);
    }
    static void gtk_label_class_init (GtkLabelClass *class)
    {
      GObjectClass *gobject_class = G_OBJECT_CLASS (class);
      
      gobject_class->finalize = gtk_label_finalize;
    }

  - the GtkObject::destroy signal can now be emitted multiple times on an object.
    ::destroy implementations should check that make sure that they take this
    into account, by checking to make sure that resources are there before
    freeing them. For example:
    if (object->foo_data)
      { 
        g_free (object->foo_data);
        object->foo_data = NULL;
      }

    Also, ::destroy implementations have to release object references that
    the object holds. Code in finalize implementations such as:
    if (object->adjustment)
      {
        gtk_object_unref (object->adjustment);
        object->adjustment = NULL;
      }
    have to be moved into the ::destroy implementations. The reason for doing
    this is that all object reference cycles should be broken at destruction 
    time.