Change background colour of a Frame

["Xiangfei Jia" <xjianz gmail com>]

I'm a beginner of gtkmm programmer. I have been trying to change the
background of a frame for quite a long time, but not successful.I used
Gtk::Color and frame.modify_bg() function. Can I get some help for
this???

fei

Part of the code:
Gtk::Color c;
c.set_red(0);
c.set_blue(6000);
c.set_green(0);

modify_bg(Gtk::STATE_NORMAL, c);