gtk/popover_since_3_18.go
func (p *Popover) SetDefaultWidget(widget IWidget) {
	C.gtk_popover_set_default_widget(p.native(), widget.toWidget())
}
func (p *Popover) SetDefaultWidget(widget IWidget) {
	C.gtk_popover_set_default_widget(p.native(), widget.toWidget())
}
//void
//gtk_popover_set_default_widget (GtkPopover *popover, GtkWidget *widget);