gtk_box_pack_start (GTK_BOX (hbox), de->cell_ref_label, FALSE, FALSE, 0);
gtk_box_pack_start (GTK_BOX (hbox), de->datum_entry, TRUE, TRUE, 0);
gtk_box_pack_start (GTK_BOX (hbox), de->cell_ref_label, FALSE, FALSE, 0);
gtk_box_pack_start (GTK_BOX (hbox), de->datum_entry, TRUE, TRUE, 0);