set_tearoff_state() when set to true creates a non-resizeable, decorated, top-level window, sized to fit the menu contents and iconized in the task bar. The torn-off menu does not need a further parent window, and can act as a standalone widget in its own right.

Where the same menu has also been set as a submenu on an existing GtkMenuItem or as a popup, the menu data is displayed in the currently-visible menu shell.

Note that the GtkMenu in this form is not and cannot be made modal. It could be described as a persistent popup.

It is not possible to connect directly to the tearoff window housing the menu, because it has not been exposed as a property in PHP-GTK - with good reason, as the reference counting has been juggled in GTK+ to make the widget possible in the first place. In order to connect the window's delete event to something meaningful, you will need to do something like this:

<?php

dl('php_gtk.' . (strstr(PHP_OS, 'WIN') ? 'dll' : 'so'));

function exit_activated($menu) {
$menu->destroy();
}

$menu = &new GtkMenu();
$window = $filemenu->parent;
$window->ref();
$window->set_flags(GTK_HAS_GRAB);
$menu->connect_object('destroy', array('gtk', 'main_quit'));

/*  Append and connect your menu items here, but note that any exit item
 must call $menu->destroy() rather than the usual gtk::main_quit(), in
 order to avoid the main loop being quitted twice over  */

$exit = &new GtkMenuItem("Exit");
$exit->connect_object('activate', 'exit_activated', $menu);

$menu->set_title("Tested!");
$menu->set_tearoff_state(true);
$menu->show_all();

gtk::main();

?>

You will also spot that this means the menu needs to be rebuilt any time it is called.