// Create the dialog window:
    $fs = &new GtkFileSelection("Save file");

// Get a handle to the Ok button:
    $ok_button = $fs->ok_button;
// Connect a function:
    $ok_button->connect("clicked", "enddialog");
// Connect the destroy action on the dialog window:
    $ok_button->connect_object("clicked", "destroy", $fs);

It is not currently possible to do it this way:

// Create the dialog window
    $fs = &new GtkFileSelection("Save file");

// Connect a function
    $fs->ok_button->connect("clicked", "enddialog");
// Connect the destroy action on the dialog window
    $fs->ok_button->connect_object("clicked", "destroy", $fs);