KViewShell, a KParts::MainWindow
| Embeds a dlopened KViewPart_Iface, which is a KParts::ReadOnlyPart.
| KViewPart is such a part.
| | KViewPart embeds a dlopened KMultiPage, which is a KParts::ReadOnlyPart.
| |   (The widget is made a child widget, and the part is made a child XMLGUI client)
| | KDVI provides a KMultiPage implementation, KDVIMultiPage.