Hi, does anyone no if Gtk or Gnome can use a window id like Tk i.e. 

$id = "12345";
$window = Gtk::Window->new($id)

I no that a window id can’t be passed to the new function. But is
there a way to set it.

$window->set_id($id);

You can use gtk_widget_set_name()
http://developer.gnome.org/doc/API/gtk/gtkwidget.html#GTK-WIDGET-SET-NAME
and this is what libglade uses, to allow you to instantiate a named widget.

But the idea of an ID or name for each widget does not seem very useful.