problem by reparent of VBox

[Dimitri Holz <d holz innoventis de>]

I want to reparent a VBox (m_oVBox, which include a toolbar with 
toolbuttons) to an Gtk::Dialog (m_oDialog) by clicking on a button:
(before click a VBox is packed into a Window (MyWindow) and m_oDialog is 
a member of MyWindow)


void MyWindow::ClickOnButton()
{
   m_oDialog.show();
   m_oDialog.show_all_children();
   m_oVBox..reparent(*(m_oDialog.get_vbox()));
   m_oDialog.show_all_children();
   m_oVBox.show_all_children();
}

But the cmd-window (I'm programming on Windows XP) show an error:

Gtk-CRITICAL **: gtk_widget_realize: assertion 'GTK_WIDGET_ANCHORED 
(widget) :: GTK_IS_INVISIBLE (widget)' failed

And some (not all) of toolbuttons in the toolbar of m_oVBox aren't 
"clickable" but they will be shown. What I do wrong or how can I solve 
this problem?