Running any app that loads something out of an xml file with libglademm, a
bunch of warnings is printed on stderr. E.g. the output of the example
'basic' reads:

(lt-basic:9356): glibmm-WARNING **: Glib::Object::Object(GObject*): An
object of type 'gtkmm__GladeXML' was created directly via g_object_new().
The Object::Object(const Glib::ConstructParams&) constructor should be used
instead.
This could happen if the C instance lived longer than the C++ instance, so
that a second C++ instance was created automatically to wrap it. That would
be a gtkmm bug that you should report.

(lt-basic:9356): glibmm-WARNING **: Glib::Object::Object(GObject*): An
object of type 'gtkmm__GtkDialog' was created directly via g_object_new().
The Object::Object(const Glib::ConstructParams&) constructor should be used
instead.
This could happen if the C instance lived longer than the C++ instance, so
that a second C++ instance was created automatically to wrap it. That would
be a gtkmm bug that you should report.

(lt-basic:9356): gtkmm-WARNING **: gtkmm: Attempt to call Gtk::manage() on
a Gtk::Window, but a Gtk::Window has no parent container to manage its
lifetime.

(lt-basic:9356): glibmm-WARNING **: Glib::Object::Object(GObject*): An
object of type 'gtkmm__GtkButton' was created directly via g_object_new().
The Object::Object(const Glib::ConstructParams&) constructor should be used
instead.
This could happen if the C instance lived longer than the C++ instance, so
that a second C++ instance was created automatically to wrap it. That would
be a gtkmm bug that you should report.


Since I'm not sure whether this is a libglademm or a gtkmm bug I'm
reporting where the bug occurs.