source: Replace Widget

import pygtk
pygtk.require("2.0")
import gtk

NAME="Replace Widget"
	
class t_replace_widget(gtk.Window):
	def __init__(self):
		gtk.Window.__init__(self)

		self.set_title("Replace Widget")
		self.set_geometry_hints(min_width=300, min_height=200)
		self.connect("destroy", gtk.main_quit)

		self.current_widget = None
		self.cpt = 0
		
		s = gtk.ScrolledWindow()
		s.show()
		self.add(s)
		
		self.box = gtk.VBox(2)
		self.box.set_homogeneous(False)
		self.box.set_spacing(5)
		self.box.show()
		s.add_with_viewport(self.box)
		
		
		box2 = gtk.HBox(2)
		b = gtk.Button("set a label widget")
		b.connect("clicked", self.on_button1_clicked)
		b.show()
		box2.pack_start(b)

		b = gtk.Button("set a button")
		b.connect("clicked", self.on_button2_clicked)
		b.show()
		box2.pack_end(b)
		box2.show()

		self.box.pack_end(box2, expand=False, fill=False)

	def on_button1_clicked(self, widget):
		l = gtk.Label("Label: %s" % self.cpt)
		self.cpt += 1
		
		l.show()
		if self.current_widget is not None:
			self.box.remove(self.current_widget)
		self.current_widget = l
		self.box.pack_start(l)
		print "button1 clicked"

	def on_button2_clicked(self, widget):
		print "button2 clicked"
		b = gtk.Button("Button: %s" % self.cpt)
		b.show()
		self.cpt += 1

		if self.current_widget is not None:
			self.box.remove(self.current_widget)
		self.current_widget = b
		self.box.pack_start(b)

t = t_replace_widget()
t.show()
gtk.main()