import wx

hint = """
1. Click the "Browse" button.
2. Select a Drive.
3. Click "OK".
4. OnDir() is called after self.gdc is destroyed.
If self.gdc.GetPath() is called, nasty things happen.
"""

class Dlg(wx.Dialog):
    def __init__(self, start=''):
        wx.Dialog.__init__(self, None, -1, "Select a folder", size=(700,500), style=wx.DEFAULT_DIALOG_STYLE|wx.RESIZE_BORDER)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.gdc = wx.GenericDirCtrl(self, -1, dir=start, size=(200,225), style=wx.DIRCTRL_DIR_ONLY)
        sizer.Add(self.gdc, 1, wx.EXPAND|wx.ALL, 5)
        okay = wx.Button(self, wx.ID_OK)
        sizer.Add(okay, 0, wx.ALL, 5)
        self.SetSizer(sizer)
        sizer.Fit(self)

        self.tree = self.gdc.GetTreeCtrl()
        self.tree.Bind(wx.EVT_TREE_SEL_CHANGED, self.OnDir)

    def OnDir(self, evt):
        print 'OnDir',evt
##        xxx = self.gdc.GetPath() # crashes
##        print 'xxx',xxx

class OuterDlg(wx.Dialog):
    def __init__(self):
        wx.Dialog.__init__(self, None, -1, "Outer dialog")
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(wx.StaticText(self, -1, hint), 0, wx.ALL, 5)
        fileButton = wx.Button(self, -1, "&Browse...")
        fileButton.Bind(wx.EVT_BUTTON, self.OnBrowse)
        sizer.Add(fileButton, 0, wx.ALL, 5)
        self.SetSizer(sizer)
        sizer.Fit(self)

    def OnBrowse(self, evt):
        dlg = Dlg()
        dlg.ShowModal()
        print 'before destroy'
        dlg.Destroy()
        print 'after destroy'

if __name__=='__main__':
    app = wx.PySimpleApp()
    dlg = OuterDlg()
    dlg.ShowModal()
    dlg.Destroy()