GtkScrollView contents & its GtkViewport contents

[Andrew Wood <ajwood theiet org>]

Am I right in thinking a GtkScrolledWindow can only have 1 child (a 
GtkViewPort) and that the GtkViewPort can only have one child also?

If this is correct.  Having added a widget a GtkVBox to a 
GtkScrolledWindow using:

gtk_scrolled_window_add_with_viewport(GTK_SCROLLED_WINDOW(scrollview),GTK_WIDGET(vbox));

How can I then remove the vbox and its viewport from the 
GtkScrolledWindow so the GtkScrolledWindow has no children, so that 
gtk_scrolled_window_add_with_viewport can be called again

Would it be correct to use

gtk_bin_get_child(GTK_BIN(scrollview))=NULL