Some "reparented" widgets not shown immediately

[Luca <elvez84 gmail com>]

Hi, I'm using glade to develop the GUI, and I use
Gnome::Glade::Xml::reparent_widget() to allow an area of the main
window (in particular, the right portion of a Gtk::HPaned) to display
different widgets dynamically.
Some kind of widgets are shown immediately after I call
reparent_widget().  Others are displayed after some user interaction,
such as moving or resizing the main window.
Apparently, the problematic widgets are intially directly contained by
a Gtk::Window.
Those windows are marked as not visible since I want only the main
window to display, not all windows I used in the glade file.
I tried to force the display of widgets in various ways (by using
Gdk::Window::invalidate_rect(), Gtk::Widget::queue_draw() and others I
don't remember) but to no avail.
Do you have any explanation for this strange behavior?

Thanks for any help,

Luca