invalid unclassed pointer?

["Dugas, Alan" <alan dugas analog com>]

I've written a function that creates a window with a combo box and a drawing
area.  The drawing area is connected to the "configure" and "expose" events and
passes the GTK_WIDGET(combo) to the function called.  However, when the progam
reaches the callback function, I keep getting the following message just prior
to segfaulting;

Gtk-WARNING **: invalid unclassed pointer in cast to 'GtkCombo'.

The callback function is declared as:
void draw_histogram(GtkWidget *calling_widget, GtkWidget *widget)

The signal connections, which occur after the combo widget is created, realized,
and shown, are as follows:
gtk_signal_connect(GTK_OBJECT(drawing_area), "configure_event",
GTK_SIGNAL_FUNC(draw_histogram), GTK_WIDGET(combo));
gtk_signal_connect(GTK_OBJECT(drawing_area), "expose_event",
GTK_SIGNAL_FUNC(draw_histogram), GTK_WIDGET(combo));

The line of code triggering the warning, and subsequent segfault, is:
combo = GTK_WIDGET(combo);
WHere combo is declared as follows:
GtkWidget *combo;

I've tried to realize the GtkCombo widget to no avail and everything else looks
proper.  What is warning trying to tell me?  Is this some sort of weird scope
issue?  Any and all responses would be appreciated!



				-- Stupid Genius