Gtk::Stock::CANCEL

[ArbolOne <arbolone gmail com>]

Hello,
I am trying to add a stock icon to a button like this:
this->btnCancel   =  Gtk::manage(new Gtk::Button(Gtk::Stock::CANCEL));
this is supposed to display a button with a X next to it (X Cancel), 
just like the Accept button in the example just above the description of 
~Button(), which display a folded arrow pointing to the left 
[http://library.gnome.org/devel/gtkmm/unstable/classGtk_1_1Button.html]

However, the button in my application does not display the intended 
image, does anyone know what I am doing wrong?

TIA