void gtk_tree_item_set_subtree (GtkTreeItem *tree_item,
GtkWidget *subtree);
void gtk_tree_item_remove_subtree (GtkTreeItem *tree_item);
void gtk_tree_item_set_subtree (GtkTreeItem *tree_item,
GtkWidget *subtree);
void gtk_tree_item_remove_subtree (GtkTreeItem *tree_item);