[gtkmm] Submenu slots don't get called

[patrick <patrick-oliver-schmidt gmx de>]

Hi all,

I'm having trouble with submenus in a popup menu.
The submenu gets filled and then attached to the parent item via  
MenuItem::set_submenu.
After that, Gtk::Menu::accelerate is called with the main window as 
argument for the toplevel menu,
and the respective parent menus for the submenus.
Everything looks fine, except that not one message slot gets called for 
any of
the submenus, while the first level works.

What am I forgetting, any ideas?

Another, not so urgent but still as strange problem:
When the mouse hovers over a menu item with a submenu attached to it, 
the message slot gets called.
Of course, I have to leave the message handler empty because of that, 
but I'd rather like to actually use the submenu item
like any other menu item, is that possible?