static guint tree_column_signals[LAST_SIGNAL] = { 0 };
-G_DEFINE_TYPE_WITH_CODE (GtkTreeViewColumn, gtk_tree_view_column, GTK_TYPE_OBJECT,
+G_DEFINE_TYPE_WITH_CODE (GtkTreeViewColumn, gtk_tree_view_column, G_TYPE_INITIALLY_UNOWNED,
G_IMPLEMENT_INTERFACE (GTK_TYPE_CELL_LAYOUT,
gtk_tree_view_column_cell_layout_init)
G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,