wxPython and thread memory problems?

Hi,

I took an example from wxPython with the IE web browser and
created a refresh button to automatically refresh a web page in 5
second intervals. But I notice that the memory utilization in Python
keeps increasing over time. Can anyone tell me why this is happening?
Here is my code:

=============== =============== =============== =============== =============== =

import wx, re
import time, thread
from urlparse import *

if wx.Platform == '__WXMSW__':
import wx.lib.iewin as iewin

refresh = 0

#----------------------------------------------------------------------

class TestPanel(wx.Pa nel):
def __init__(self, parent, frame=None):
wx.Panel.__init __(
self, parent, -1,
style = wx.TAB_TRAVERSA L |
wx.CLIP_CHILDRE N |
wx.NO_FULL_REPA INT_ON_RESIZE
)

self.current = "http://www.google.com"
self.frame = frame

if frame:
self.titleBase = frame.GetTitle( )

sizer = wx.BoxSizer(wx. VERTICAL)
btnSizer = wx.BoxSizer(wx. HORIZONTAL)

self.ie = iewin.IEHtmlWin dow(self, -1, style =
wx.NO_FULL_REPA INT_ON_RESIZE)

btn = wx.Button(self, -1, "Open", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnOpenButt on, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "Home", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnHomeButt on, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "<--", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnPrevPage Button, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "-->", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnNextPage Button, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "Stop", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnStopButt on, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "Search", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnSearchPa geButton, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "Refresh", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnRefreshP ageButton, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

btn = wx.Button(self, -1, "AutoRefres h", style=wx.BU_EXA CTFIT)
self.Bind(wx.EV T_BUTTON, self.OnAutoRefr eshPageButton, btn)
btnSizer.Add(bt n, 0, wx.EXPAND|wx.AL L, 2)

txt = wx.StaticText(s elf, -1, "Location:" )
btnSizer.Add(tx t, 0, wx.CENTER|wx.AL L, 2)

self.location = wx.TextCtrl(sel f, -1, "",
style=wx.TE_PRO CESS_ENTER)

self.location.B ind(wx.EVT_CHAR , self.OnLocation Return)
btnSizer.Add(se lf.location, 1, wx.EXPAND|wx.AL L, 2)

sizer.Add(btnSi zer, 0, wx.EXPAND)
sizer.Add(self. ie, 1, wx.EXPAND)

self.ie.LoadUrl (self.current)

self.SetSizer(s izer)
# Since this is a wxWindow we have to call Layout ourselves
self.Bind(wx.EV T_SIZE, self.OnSize)

# Hook up the event handlers for the IE window
self.Bind(iewin .EVT_DocumentCo mplete, self.OnDocument Complete,
self.ie)

thread.start_ne w_thread(self.r efresh_url, (5,))

def OnSize(self, evt):
self.Layout()

def OnLocationRetur n(self, evt):
if evt.KeyCode() == wx.WXK_RETURN:
self.ie.Navigat e(self.location .GetValue(),
iewin.NAV_NoRea dFromCache | iewin.NAV_NoWri teToCache)
else:
evt.Skip()

def OnOpenButton(se lf, event):
dlg = wx.TextEntryDia log(self, "Open Location",
"Enter a full URL or local path",
self.current, wx.OK|wx.CANCEL )
dlg.CentreOnPar ent()

if dlg.ShowModal() == wx.ID_OK:
self.current = dlg.GetValue()
self.ie.Navigat e(self.current,
iewin.NAV_NoRea dFromCache | iewin.NAV_NoWri teToCache)

dlg.Destroy()

def OnHomeButton(se lf, event):
self.ie.GoHome( ) ## ET Phone Home!

def OnPrevPageButto n(self, event):
self.ie.GoBack( )

def OnNextPageButto n(self, event):
self.ie.GoForwa rd()

def OnStopButton(se lf, evt):
self.ie.Stop()

def OnSearchPageBut ton(self, evt):
self.ie.GoSearc h()

def OnRefreshPageBu tton(self, evt):
self.ie.Refresh Page(iewin.REFR ESH_COMPLETELY)

def OnAutoRefreshPa geButton(self, evt):
global refresh
refresh = not refresh

def refresh_url(sel f, delay):
global refresh
while (1):
time.sleep(dela y)
if refresh:
self.ie.Navigat e(self.ie._get_ LocationURL(),
iewin.NAV_NoRea dFromCache |
iewin.NAV_NoWri teToCache)

def OnDocumentCompl ete(self, evt):
self.current = evt.URL
self.location.S etValue(self.cu rrent)

class Frame(wx.Frame) :
def __init__(self, parent=None, id=-1, title='Title',
pos=wx.DefaultP osition, size=(640, 480)):
wx.Frame.__init __(self, parent, id, title, pos, size)

self.attr = {}
self.attr['panel'] = TestPanel(self)

class App(wx.App):
def OnInit(self):
self.attr = {}

self.attr['frame'] = Frame(title='My Window')
self.attr['frame'].Show()
self.SetTopWind ow(self.attr['frame'])

return True

def main():
app = App()
app.MainLoop()

if __name__ == '__main__':
main()
#----------------------------------------------------------------------