Help With GTKMM and classes

[Mike Eller <gtkmike earthlink net>]

Hello list,

This is my first post!

I am just getting started with GTKMM and getting back into C++.
Here is my dilema...

I have a small project I am working on and so far there is a main class 
which contains the main function. There is also an Interface class where 
I want to instantiate the main window of the project and container 
objects (like notebooks and boxes).
I want to add a menu that is another class (file). I created a class 
that extends the MenuBar class like this:

class MainMenu : public Gtk::MenuBar

then add all the code to create the menus and items.

So, then I include the MainMenu.h file as an include in the Interface.cc 
file.  And create an instance of it
like this: 
MainMenu mm;

Then, to add the MainMenu to the window, I pack it in a vertical box 
like so:
m_VBox_Top.pack_start(mm, Gtk::PACK_SHRINK);

But for some reason this does not work.

So, can anyone point me in the right direction here as to what I am 
doing wrong?

Any and all assistance is greatly appreciated.

Thanks,
Mike