GtkLabel max-width-chars with ellipsize broken?

[infirit <infirit gmail com>]

Hi, I have been trying to use "max-width-chars" with ellipsize on a
label that acts as a page label for a notebook with zero success. It
appears it is completely ignored as whatever I use, -1 to 200 nothing
ever changes how it looks. How it looks is either we only see a single
character with ellipses or just ellipses.

Am I missing something? is this the correct way to force a certain width
on the label?

Thx
~infirit

from gi.repository import Gtk, Pango

class MyWindow(Gtk.Window):
    def __init__(self, *args, **kwargs):
        super().__init__(default_width=400, default_height=300,
                         *args, **kwargs)
        self.connect("delete-event", Gtk.main_quit)

        self.notebook = Gtk.Notebook()
        self.add(self.notebook)
        for n in (1,2,3):
            # We should see the first 20 then ellipse
            label_text = "012345678901234567890"
            page_label = Gtk.Label(
                label_text,
                max_width_chars=20,
                ellipsize=Pango.EllipsizeMode.END,
                halign=Gtk.Align.CENTER)
            page_label.set_tooltip_text(label_text)
            page_content = Gtk.Image.new_from_icon_name("go-home",
Gtk.IconSize.DIALOG)
            self.notebook.insert_page(page_content, page_label, n)

window = MyWindow()
window.show_all()

Gtk.main()