segfault on liststore append()

["Jeremy Shivers" <shivers53 hotmail com>]

I am trying to have one window add data to a treeview column in a different 
window and I am getting a segfault when the list store reference pointer 
tries to append(). Below is the code used.

window1.h
---------
#include <gtkmm.h>

class CWindow1 : public Gtk::Window
{
public:
	CWindow1(Gtk::Window *parent);
private:
	class CColumnRecord : public Gtk::TreeModelColumnRecord
	{
	public:
		CColumnRecord() { add(Column1); }

		Gtk::TreeModelColumn<Glib::ustring> Column1;
	};

	Glib::RefPtr<Gtk::ListStore> _RPListStore;
	const CColumnRecord _ColumnRecord;

	Gtk::ScrolledWindow *_ScrolledWindow;
	Gtk::TreeView *_TreeView;

	virtual void onAddColumnData();
};

window1.cpp
-----------
#include <sigc++/sigc++.h>
#include "window1.h"

using namespace Gdk;
using namespace Gtk;

CWindow1::CWindow1() : Window(Gtk::WINDOW_TOPLEVEL)
{
	set_title("Window1");
	set_size_request(500, 500);
	set_resizable(false);
	set_modal(true);
	set_position(WIN_POS_CENTER);
	set_type_hint(WINDOW_TYPE_HINT_NORMAL);

	_ScrolledWindow = manage(new ScrolledWindow());
	_TreeView = manage(new TreeView());

	_TreeView->set_flags(CAN_FOCUS);
	_TreeView->set_headers_visible(true);
	_TreeView->set_rules_hint(true);
	_TreeView->set_reorderable(true);
	_TreeView->set_enable_search(true);
	_ScrolledWindow->set_flags(CAN_FOCUS);
	_ScrolledWindow->set_shadow_type(SHADOW_IN);
	_ScrolledWindow->set_policy(POLICY_AUTOMATIC, POLICY_AUTOMATIC);
	_ScrolledWindow->set_placement(CORNER_TOP_LEFT);
	_ScrolledWindow->add(*_TreeView);
	add(*_ScrolledWindow);

	_RPListStore = ListStore::create(_ColumnRecord);
	_TreeView->set_model(_RPListStore);
	int columnCount = _TreeView->append_column("Column1", 
_ColumnRecord.Column1);
	TreeViewColumn *tvc = _TreeView->get_column(columnCount - 1);
	if (tvc)
	{
		tvc->set_resizable(true);
		tvc->set_clickable(true);
		tvc->set_sizing(TREE_VIEW_COLUMN_AUTOSIZE);
	}

	_ScrolledWindow->show();
	_TreeView->show();
}

void CWindow1::onAddColumnData()
{
	// segfaults here when called from window2
	TreeRow row = *(_RPListStore->append());
}

window2.h
---------
#include <sigc++/sigc++.h>
#include <gtkmm.h>

class CWindow1;

class CWindow2 : public Gtk::Window
{
public:
	CWindow2(Gtk::Window *parent);

private:
	Gtk::Button *_Button;
	virtual void onButtonClicked();
	sigc::signal<void> _ButtonClicked;
	CWindow1 *_Parent;
};

window2.cpp
-----------
#include "window2.h"
#include "window1.h"

using namespace Gtk;
using namespace Gdk;
using namespace Glib;

CWindow2::CWindow2(Window *parent) : Window(Gtk::WINDOW_TOPLEVEL)
{
	_Parent = (CWindow1 *)parent;

	set_title("Window2");

	set_size_request(500, 500);
	set_resizable(false);
	set_modal(true);
	set_position(WIN_POS_CENTER);
	set_transient_for(*parent);
	set_type_hint(WINDOW_TYPE_HINT_NORMAL);

	_Button = manage(new Button("Click Me"));
	_Button->set_flags(CAN_FOCUS);
	_Button->set_flags(CAN_DEFAULT);
	_Button->set_relief(RELIEF_NORMAL);
	add(*_Button);
	_Button->show();

	_Button->signal_clicked().connect(sigc::mem_fun(*this, 
&CWindow2::onButtonClicked), false);

	// Doesn?t compile this way. Must do it the way below
	//_ButtonClicked.connect(sigc::mem_fun(*_Parent, 
&CWindow1::onAddColumnData));

	sigc::slot<void> s = sigc::mem_fun(*_Parent, &CWindow1::onAddColumnData);
	_ButtonClicked.connect(s);

}

void CWindow2::onButtonClicked()
{
	_ButtonClicked.emit();
	hide();
}

main.cpp
--------
#include <gtkmm/main.h>
#include "window1.h"

int main(int argc, char *argv[])
{
	Gtk::Main m(&argc, &argv);
	CWindow1 *w = new CWindow1();
	m.run(*w);
	delete w;

	return 0;
}

Am I doing something wrong, or is there a better way of accomplishing this?

gtk 2.6.0
glib 2.6.0
gtkmm 2.4
glibmm 2.4
libsigc++ 2.0.9

Thanks in advance
	visy