Simple countdown progress bar remake

I've been warned on reddit my countdown progress bar implementation explained here is messy and wouldn't work on Windows OS because changing widgets is valid only from the GUI thread and I must admit, a special thread object for the purpose of updating the widget really looks messy, but I really didn't test it to see if it works on Windows. Today I reworked the code anyway, merging all the previous stuff in one object that builds GUI and acts as a timer at the same time. Also I made some minor improvements. Simple countdown timer is now even more simpler:

 1 import time, gtk 
 2 from threading import Thread, Event 
 3 
 4 gtk.gdk.threads_init() # initialize threads right away 
 5 
 6 class cdProgressBar(Thread): 
 7     def __init__(self, time = 10): 
 8         Thread.__init__(self) 
 9         self.time = self.tot_time = time 
10         
11         self.builder = gtk.Builder() 
12         self.builder.add_from_file('progressbar_countdown.glade') 
13         self.window = self.builder.get_object('cd_window') 
14         self.progressbar = self.builder.get_object('cd_progressbar') 
15         self.set_progressbar() 
16         
17         self.builder.connect_signals({ 
18             'on_cd_window_delete_event'    : self.quit, 
19             'on_cd_startbutton_clicked'    : self.startbutton_clicked, 
20             'on_cd_pausebutton_clicked'    : self.pausebutton_clicked 
21         }) 
22         
23         # threading 
24         self.unpause = Event() 
25         self.restart = False 
26         self.setDaemon(True) # stop the thread on exit 
27         
28     def main(self): 
29         self.window.show_all() 
30         self.start() # start the thread 
31         gtk.main() 
32         
33     def quit(self, widget, data = None): 
34         gtk.main_quit() 
35         
36     def startbutton_clicked(self, widget, data = None): 
37         if not self.unpause.isSet(): 
38             self.unpause.set() 
39         self.restart = True 
40         
41     def pausebutton_clicked(self, widget, data = None): 
42         if self.unpause.isSet(): 
43             self.unpause.clear() # pause the countdown timer 
44         else: 
45             self.unpause.set() 
46             
47     def set_progressbar(self): 
48         self.progressbar.set_text(str(self.time)) 
49         self.progressbar.set_fraction(self.time/float(self.tot_time)) 
50          
51     def run(self): 
52         while True: 
53             self.unpause.wait() # wait the self.unpause.isSet() 
54             if self.restart: 
55                 self.time = self.tot_time 
56                 self.restart = False 
57             self.set_progressbar() 
58             time.sleep(1) 
59             if self.time != 0: 
60                 self.time -= 1 
61             
62 cd_window = cdProgressBar() 
63 cd_window.main()    

Countdown Progress Bar is designed using glade interface designer like this. Code is tested and it's working under Windows and under Linux as well.