from gi.repository import Gtk
class ButtonWindow(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self, title="Button Demo")
        self.set_border_width(10)
        self.hbox = Gtk.Grid()
        self.hbox.set_reallocate_redraws(True)
        self.add(self.hbox)
        self.button = Gtk.Button("Click Me")
        self.button.connect("clicked", self.on_click_me_clicked)
        self.hbox.attach(self.button, 1, 1, 1, 1)
        button2 = Gtk.Button(stock=Gtk.STOCK_OPEN)
        button2.connect("clicked", self.on_open_clicked)
        self.hbox.attach(button2, 1, 2, 1, 1)
        button3 = Gtk.Button("_Close", use_underline=True)
        button3.connect("clicked", self.on_close_clicked)
        self.hbox.attach(button3, 1, 3, 1, 1)
    def on_click_me_clicked(self, button):
        self.button.destroy()
    def on_open_clicked(self, button):
        self.button = Gtk.Button("Click Me")
        self.button.connect("clicked", self.on_click_me_clicked)
        self.hbox.attach(self.button, 1, 1, 1, 1)
        self.show_all()
    def on_close_clicked(self, button):
        print("Closing application")
        Gtk.main_quit()
win = ButtonWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()

from gi.repository import Gtk
class ButtonWindow(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self, title="Button Demo")
        self.set_border_width(10)
        self.hbox = Gtk.Grid()
        self.hbox.set_reallocate_redraws(True)
        self.add(self.hbox)
        self.button = Gtk.Button("Click Me")
        self.button.connect("clicked", self.on_click_me_clicked)
        self.hbox.attach(self.button, 1, 1, 1, 1)
        button2 = Gtk.Button(stock=Gtk.STOCK_OPEN)
        button2.connect("clicked", self.on_open_clicked)
        self.hbox.attach(button2, 1, 2, 1, 1)
        button3 = Gtk.Button("Modal window", use_underline=True)
        button3.connect("clicked", self.mod_win)
        self.hbox.attach(button3, 1, 3, 1, 1)
    def mod_win(self, widget):
        def w_d(*args):
            win.destroy()
        def del_but(*args):
            print(args)
            self.button.destroy()
            self.label = Gtk.Label('New')
            self.hbox.attach(self.label, 1, 1, 1, 1)
            self.show_all()
        win = Gtk.Window(default_height=50, default_width=300)
        win.set_modal(True)
        win.set_transient_for(self)
        win.connect("delete-event", w_d)
        button = Gtk.Button('Delet')
        button.connect("clicked", del_but)
        box = Gtk.Box.new(Gtk.Orientation.VERTICAL, 5)
        box.pack_start(button, True, True, 0)
        win.add(box)
        win.show_all()
    def on_click_me_clicked(self, button):
        self.button.destroy()
    def on_open_clicked(self, button):
        self.button = Gtk.Button("Click Me")
        self.button.connect("clicked", self.on_click_me_clicked)
        self.hbox.attach(self.button, 1, 1, 1, 1)
        self.show_all()
    def on_close_clicked(self, button):
        print("Closing application")
        Gtk.main_quit()
win = ButtonWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()