wxPython CollapsiblePane strange clipping issue

This is a follow up from allocating more size in sizer to wx.CollapsiblePane when expanded.

EDIT: The answer to that question solved my original problem, which was that nothing moved when I expanded or collapsed a pane, but now I've encountered another bug. While things do move properly, the buttons seem to smear out over each other as shown in the image below. Mousing over a button seems to force it to redraw properly over the rest of the mess, but it leaves a bunch of random button pieces drawn behind and around it.

I've done my absolute best to replicate this bug in a sample app, but I can't. I'm just looking for leads here. Does anyone have any idea what might cause the kind of issue shown below? It only happens after expanding and collapsing some of the upper panes.

For what it's worth, code below is for a sample app that looks very similar, but for some reason doesn't cause the same problems. EDIT Also for what it's worth, here's a link to the full source code for the GUI of my project which generated 开发者_开发技巧the screenshot below. http://code.google.com/p/dicom-sr-qi/source/browse/gui/main.py?r=8a876f7b4a034df9747a2c1f2791258f671e44b1

import wx

class SampleSubPanel(wx.Panel):
    def __init__(self, *args, **kwargs):
        wx.Panel.__init__(self, *args, **kwargs)
        sizer = wx.BoxSizer(wx.HORIZONTAL)
        sizer.Add(wx.StaticText(self, 1, "A label"))
        sizer.Add(wx.SpinCtrl(self))
        self.SetSizer(sizer)

class SampleCollapsiblePane(wx.CollapsiblePane):
    def __init__(self, *args, **kwargs):
        wx.CollapsiblePane.__init__(self,*args,**kwargs)
        sizer = wx.BoxSizer(wx.VERTICAL)
        for x in range(2):
            sizer.Add(wx.CheckBox(self.GetPane(), label = str(x)))
            sizer.Add(SampleSubPanel(self.GetPane()))
        self.GetPane().SetSizer(sizer)
        self.Bind(wx.EVT_COLLAPSIBLEPANE_CHANGED, self.on_change)

    def on_change(self, event):
        self.GetParent().Layout()

class SampleSubPanel2(wx.Panel):

    def __init__(self, *args, **kwargs):
        wx.Panel.__init__(self, *args, **kwargs)
        sizer = wx.BoxSizer(wx.VERTICAL)
        for x in range(2):
            sizer.Add(SampleCollapsiblePane(self, label = str(x)), 0)
        self.SetSizer(sizer)


class Main_Frame(wx.Frame):
    def __init__(self, *args, **kwargs):
        wx.Frame.__init__(self, *args, **kwargs)
        self.main_panel = wx.Panel(self)
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(wx.Panel(self.main_panel, style=wx.RAISED_BORDER),1, wx.EXPAND)
        sizer.Add(SampleSubPanel2(self.main_panel, style = wx.RAISED_BORDER),2, wx.EXPAND )
        sizer.Add(wx.Button(self.main_panel,label= "a button"),0,wx.ALIGN_CENTER)
        self.main_panel.SetSizer(sizer)


class SampleApp(wx.App):
    def OnInit(self):
        frame = Main_Frame(None, title = "Sample App")
        frame.Show(True)
        frame.Centre()
        return True

def main():
    app = SampleApp(0)
    app.MainLoop()

if __name__ == "__main__":
    main()

If I am getting you right, you want the code here - allocating more size in sizer to wx.CollapsiblePane when expanded to work properly. The reason it did not work was you forgot to bind the wx.EVT_COLLAPSIBLEPANE_CHANGED. Here is a code which worked for me -

import wx

class SampleCollapsiblePane(wx.CollapsiblePane):
    def __init__(self, *args, **kwargs):
        wx.CollapsiblePane.__init__(self,*args,**kwargs)
        sizer = wx.BoxSizer(wx.VERTICAL)

        for x in range(5):
            sizer.Add(wx.Button(self.GetPane(), label = str(x)))

        self.GetPane().SetSizer(sizer)
        self.Bind(wx.EVT_COLLAPSIBLEPANE_CHANGED, self.on_change)

    def on_change(self, event):
        self.GetParent().Layout()

class Main_Frame(wx.Frame):
    def __init__(self, *args, **kwargs):
        wx.Frame.__init__(self, *args, **kwargs)

        self.main_panel = wx.Panel(self)
        sizer = wx.BoxSizer(wx.VERTICAL)

        for x in range(5):
            sizer.Add(SampleCollapsiblePane(self.main_panel, label = str(x)), 0)

        self.main_panel.SetSizer(sizer)


class SampleApp(wx.App):
    def OnInit(self):
        frame = Main_Frame(None, title = "Sample App")
        frame.Show(True)
        frame.Centre()
        return True

def main():
    app = SampleApp(0)
    app.MainLoop()

if __name__ == "__main__":
    main()

EDIT: Looks like it may be a bug in wxPython running on windows. Below is screen shot of the the exact same code that has problems on Windows running on Ubuntu with no problems.