[Gtk-sharp-list] `widget->parent == NULL' failed

[Black Fox]

> (<unknown>:1948): Gtk-CRITICAL **: file gtkwidget.c: line 3943 (gtk_widget_set_p
> arent): assertion `widget->parent == NULL' failed

Without the source code it's not easy. But this line said that you try 
to add a widget to an element and that this widget already have a parent.

But it may not be exactly that, as when i trigger such situation (Mono 
CVS from Windows Installer 4, GTK# 0.18 under Windows XP)

(<unknown>:8148): Gtk-WARNING **: Attempting to add a widget with type 
GtkTreeView to a container of type GtkWindow, but the widget is already 
inside a container of type GtkScrolledWindow, the GTK+ FAQ at 
http://www.gtk.org/faq/ explains how to reparent a widget.