popovermenu.py

import gi
gi.require_version("Gtk", "3.0")
from gi.repository import Gtk

def on_click(button):
    #Toggle
    if popover.get_visible():
        popover.hide()
    else:
        popover.show_all()

#Creating the window
window = Gtk.Window(title="Popover")
window.connect("destroy", lambda w: Gtk.main_quit())

#Creating and placing a button
box = Gtk.Box(orientation = Gtk.Orientation.VERTICAL)
button = Gtk.Button.new_from_icon_name("open-menu-symbolic", 1)
button.connect("clicked", on_click)
box.add(button)
window.add(box)

#Creating a popover
popover = Gtk.PopoverMenu.new()
popover.set_relative_to(button)

pbox = Gtk.Box(orientation = Gtk.Orientation.VERTICAL)
popover.add(pbox)

one = Gtk.ModelButton.new()
one.set_label("Button One")
pbox.pack_start(one, False, False, 0)

two = Gtk.ModelButton.new()
two.set_label("Button Two")
pbox.pack_start(two, False, False, 0)

three = Gtk.ModelButton.new()
three.set_label("Button Three")
pbox.pack_start(three, False, False, 0)

window.set_size_request(200, 200)
window.show_all()

Gtk.main()