MenuItemPrivate
class MenuItemPrivate;
friend class BPrivate::MenuItemPrivate;
class MenuItemPrivate {
MenuItemPrivate(BMenuItem* menuItem);
BPrivate::MenuItemPrivate newMenuItemPrivate(newItem);
MenuItemPrivate::MenuItemPrivate(BMenuItem* menuItem)
MenuItemPrivate::SetSubmenu(BMenu* submenu)
MenuItemPrivate::Install(BWindow* window)
MenuItemPrivate::Uninstall()