[Gtk-sharp-list] Custom (subclassed) widget fails to show up in Glade based application

[Sebastian]

Hello everybody,

I use a .glade file to load all main parts of the GUI, including a few 
tabs.  As I need the same TreeView in some of the tabs, I manually wrote 
a subclass, looking like this:

public class
MyListView : Gtk.ScrolledWindow
{
     private TreeView tv;

     public MyListView ()
         : base ()
     {
         tv = new TreeView ();

	// ... do TreeView initialization, populate treeview, etc.

         tv.WidthRequest = 240;
         WidthRequest = 250;

         Child = tv;
     }
}

In Glade, I have constructed a HPaned in one tab and a VBox in another 
tab.  In the VBox I just put one label, and the HPaned I left empty on 
the left side.

The main program initialization is this:

     private void Init ()
     {
         Glade.XML gxml = new Glade.XML ("myprogram.glade", 
"MainWindow", null);
         gxml.Autoconnect (this);

         /* Setup the view tree
          */
         MyListView mlv = new MyListView ();

         tab1Pane.Pack1 (mlv, true, false);
         tab2VBox.PackEnd (mlv);

	// **A
     }

Using this starts up the GUI but leaves the HPaned empty and the VBox 
with just the label.  I tried inserting a "mlv.Show ()" and "mlv.Realize 
()" at the **A marked place, but it failed, giving the error message:

(<unknown>:6496): Gtk-CRITICAL **: gtk_widget_realize: assertion 
`GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed

I am at loss about Gtk internals and did not find a single example of 
how to properly setup a subclassed custom widget with a glade-based 
application (I have used manual subclassing in non-glade gtk# apps 
successfully).

What do I miss?

Thanks,
Sebastian