/* Expander * * GtkExpander allows to provide additional content that is initially hidden. * This is also known as "disclosure triangle". * */#include <gtk/gtk.h>static GtkWidget *window = NULL;GtkWidget *do_expander (GtkWidget *do_widget){  GtkWidget *vbox;  GtkWidget *label;  GtkWidget *expander;    if (!window)  {    window = gtk_dialog_new_with_buttons ("GtkExpander",					  GTK_WINDOW (do_widget),					  0,					  GTK_STOCK_CLOSE,					  GTK_RESPONSE_NONE,					  NULL);    gtk_window_set_resizable (GTK_WINDOW (window), FALSE);    g_signal_connect (window, "response",		      G_CALLBACK (gtk_widget_destroy), NULL);    g_signal_connect (window, "destroy",		      G_CALLBACK (gtk_widget_destroyed), &window);    vbox = gtk_vbox_new (FALSE, 5);    gtk_box_pack_start (GTK_BOX (GTK_DIALOG (window)->vbox), vbox, TRUE, TRUE, 0);    gtk_container_set_border_width (GTK_CONTAINER (vbox), 5);    label = gtk_label_new ("Expander demo. Click on the triangle for details.");    gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);    /* Create the expander */    expander = gtk_expander_new ("Details");    gtk_box_pack_start (GTK_BOX (vbox), expander, FALSE, FALSE, 0);    label = gtk_label_new ("Details can be shown or hidden.");    gtk_container_add (GTK_CONTAINER (expander), label);  }  if (!GTK_WIDGET_VISIBLE (window))    gtk_widget_show_all (window);  else    gtk_widget_destroy (window);  return window;}