interaction between widgets

[Axel <axel azerty netcourrier com>]

basically here is my problem
I have a menubar created by : GtkMenubar* create_menubar()
I have put in it the g_signal_connect for catch events like "activate",for each item of the menu. (maybe it 
is a wrong place)

Next to that I have a notebook, with a few page, and when I click in an item in the menu I d like to close 
the current page.

but I don' t know how to get the current pointer to GtkNotebook from create_menubar() or from my function 
close_page() (which is the CALLBACK designed to close the page)

I have probably made an error of "architectur" in my functions, so which is the best way to have interactions 
between items in the menubar and other widgets of the program ?
In other words : activate item in the menu bar acts on the widgets in the program.

Axel