Calling Gtk::ToggleToolButton's set_icon_widget() multiple times

[Ruud Beukema <ruudbeukema gmail com>]

Hi all,

I'm new to this mailing-list (and quite new to Gtkmm programming too),
but I joined because I have a problem to which I couldn't find an answer
through your mailing-list-archives and best friend Google.

My goal is to add a Gtk::ToggleToolButton to a Gtk::Toolbar (this
works). The Gtk::ToggleToolButton should show icon #1 in its non-active
(raised) state and icon #2 in its active (pressed) state. Here's how I
tried to accomplish this in class Foo:

----------------------------------------------------------------

/* Class Foo's private variables */
Gtk::ToggleToolButton mToggleToolButton;
Gtk::Image *pImage;

/* Class Foo's constructor */
Foo::Foo()
{
	// In this constructor the ToggleToolButton is successfully set to have
the default icon
	Glib::RefPtr<Gdk::Pixbuf> im =
Gdk::Pixbuf::create_from_file("path_to_icon_1", 22, 22, true);
	pImage = manage(new Gtk::Image(im));
	mToggleToolButton.set_icon_widget(*pImage);
	mToggleToolButton.signal_toggled().connect( sigc::mem_fun(*this,
&Foo::on_toggletoolbutton_toggled) );
}

void Foo::on_toggletoolbutton_toggled()
{
	if  ( mToggleToolButton.get_active() )
	{
		// Here I try to replace the ToggleToolButton's icon
		Glib::RefPtr<Gdk::Pixbuf> im =
Gdk::Pixbuf::create_from_file("path_to_icon_2", 22, 22, true);
		pImage = manage(new Gtk::Image(im));
		mToggleToolButton.set_icon_widget(*pImage);
	}
	else
	{
		// Icon #1 again
	}
}

----------------------------------------------------------------

I've tried the above with and without the Gtk::manage() function, both
with no luck: when the ToggleToolButton is toggled for the first time
after construction, icon #1 is removed as expected but not replaced with
icon #2. Maybe needless to say, but when the ToggleToolButton is toggled
for a second time or more it remains without icon.

What am I doing wrong here? Or can Gtk::ToggleToolButton be only set to
have an icon once? Hope you can help me out!

Regards,
Ruud