[glade--]unable to add new members to derived class

Hello,

this is probably something very stupid, but my C++ is little rusty 
(after years of Java) and I'm completely new to gtkmm & related stuff, 
so please have a patience:

I create new gtk+ project using glade - single window containing a 
label, nothing else. I set the language to C++, generate code, run 
autogen.sh, run the program, it works. Then I add a single member to 
the main window class header file:

#ifndef _WINDOW1_HH
#  include "window1_glade.hh"
#  define _WINDOW1_HH
#include "glademm_support.hh"

class window1 : public window1_glade
{  public:
   int foo;
};
#endif

run make, run the program, and get segmentation fault. If I try to use 
DDD, it apparently fails on the "Gtk::Main m(&argc, &atgv)" line in 
function main, and it reports following:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1024 (LWP 1120)]
0x4049a82e in Glib::ObjectBase::is_derived_ () from 
/usr/lib/libglibmm-2.0.so.1

My gcc is 2.95.3, glade-- is 1.1.2 and reports following when 
generating code:
Found pkg-config version 0.14.0
Generating code for gtk 2.0.8 (pkg-config), gtkmm 2.0.1 (pkg-config), 
[gnomemm 1.2.3 (pkg-config)]


Can somebody please tell what is the problem and how to fix it? I would 
like to convert to gtkmm, but I'm starting to miss Java and Swing 
already 8-)

thank you,
Bob Koutsky