+#define FRAME_GTK_WIDGET_INSTANCE_HASH_TABLE(f) (FRAME_GTK_DATA (f)->widget_instance_hash_table)
+#define FRAME_GTK_WIDGET_CALLBACK_HASH_TABLE(f) (FRAME_GTK_DATA (f)->widget_callback_hash_table)
+#define FRAME_GTK_WIDGET_CALLBACK_EX_HASH_TABLE(f) (FRAME_GTK_DATA (f)->widget_callback_ex_hash_table)
+
+/* Special data used to quickly identify the frame that contains a widget. */
+#define GTK_DATA_FRAME_IDENTIFIER "xemacs::frame"
+
+/* The hashcode in the frame hash table of a tab_control tab's callback data. */
+#define GTK_DATA_TAB_HASHCODE_IDENTIFIER "xemacs::tab_hashcode"
+
+#define GTK_DATA_GUI_IDENTIFIER "xemacs::gui_id"