GtkDialog:use-header-bar

TRUE if the dialog uses a headerbar for action buttons instead of the action-area.

For technical reasons, this property is declared as an integer property, but you should only set it to TRUE or FALSE.

Creating a dialog with headerbar

Builtin GtkDialog subclasses such as GtkColorChooserDialog set this property according to platform conventions (using the GtkSettings:gtk-dialogs-use-header setting).

Here is how you can achieve the same:

g_object_get (settings, "gtk-dialogs-use-header", &header, NULL);
dialog = g_object_new (GTK_TYPE_DIALOG, header, TRUE, NULL);

Type:gint