gtk_widget_set

[hubert fauque wanadoo fr]

Hello,
I am learning GTK; in testgtk.c there are some
calls to gtk_widget_set like the following:

      gtk_widget_set (tips_query,
		      "GtkWidget::visible", TRUE,
		      "GtkWidget::parent", box3,
		      "GtkTipsQuery::caller", button,
		      "GtkObject::signal::widget_entered", tips_query_widget_entered, toggle,
		      "GtkObject::signal::widget_selected", tips_query_widget_selected, NULL,
		      NULL);

I supposed that would be the same as:

  gtk_tips_query_set_caller (GTK_TIPS_QUERY(tips_query), GTK_WIDGET(button));
  gtk_widget_set_parent (GTK_WIDGET(tips_query), GTK_WIDGET(box3));
  gtk_signal_connect (GTK_OBJECT(tips_query), "widget_entered",
		      GTK_SIGNAL_FUNC(tips_query_widget_entered), (gpointer)toggle);
  gtk_signal_connect (GTK_OBJECT(tips_query), "widget_selected",
		      GTK_SIGNAL_FUNC(tips_query_widget_selected), NULL);
  gtk_widget_show(GTK_WIDGET(tips_query));


but if I replace the gtk_widget_set call by this I get
the error (at execution):
Gtk-CRITICAL **: file gtktipsquery.c: line 324 (gtk_tips_query_start_query): assertion `GTK_WIDGET_REALIZED (tips_query)' failed.

could somebody explain the difference?

Thanks

Hubert