The problem was that simply calling Window.show() doesn't mean that the window

The problem was that simply calling Window.show() doesn't mean that the window
is brought to the foreground. Actually, there seems to be nothing that
guarantees this, because the user's settings and choice of window manager may
ffect the behavior. However, some research and experimentation shows that
calling these two Window methods

        set_urgency_hint(true);
        present();

may not bring the window to the foreground either, but do at least causes the
user to be notified that the window wants attention, much like the way Windows
may make a taskbar icon flash orange.