wxPython blocks in thread?

[Arnaud de La Fortelle]

I am a beginner with wxPython and tried to embed a GUI within a
thread.  So I came with a simple implementation, but it does not work.
I do not understand why the following application blocks. What the
matter?

Arnaud

from wxPython.wx import *
class MyApp(wxApp):
  def OnInit(self):
    frame = wxFrame(NULL, -1, "It blocks!")
    frame.Show(true)
    self.SetTopWindow(frame)
    return true

import threading
class GUIThread(threading.Thread,object):
  def __init__(self):
    threading.Thread.__init__(self,target=self.loop)
    self.start()
  def loop(self):
    print gui_thr
    self.app = MyApp(0)
    self.app.MainLoop() # if I comment out this line, it works
    print "Ending wxLoop", self.isAlive()


gui_thr=GUIThread()
print "Ending Main thread"