OSX: wx, Grid, ChoiceEditor and empty cell -> render issue

gistfile1.py

import wx
import wx.grid

class Frame1(wx.Frame):
    def __init__(self, parent):
        wx.Frame.__init__(self, id=-1, name='', parent=None,
                          pos=wx.Point(100, 100), size=wx.Size(480, 250),
                          style=wx.DEFAULT_FRAME_STYLE, title='Spam & Eggs')
        self.SetClientSize(wx.Size(400, 250))

        self.scrolledWindow1 = wx.ScrolledWindow(id=-1,
                                                 name='scrolledWindow1', parent=self, pos=wx.Point(0, 0),
                                                 size=wx.Size(400, 250), style=wx.HSCROLL | wx.VSCROLL)

        self.grid1 = wx.grid.Grid(id=-1, name='grid1',
                                  parent=self.scrolledWindow1, pos=wx.Point(0, 0),
                                  size=wx.Size(400, 250), style=0)

        self.grid1.CreateGrid(14, 2)

        self.grid1.SetDefaultEditor(wx.grid.GridCellChoiceEditor(['A', 'B', 'C'], allowOthers=True))

        self.grid1.MakeCellVisible(13, 0)
        self.grid1.SetGridCursor(12, 0)

        self.grid1.Bind(wx.grid.EVT_GRID_EDITOR_CREATED, self.editor_created)
        self.grid1.Bind(wx.grid.EVT_GRID_EDITOR_SHOWN, self.editor_shown)

    def editor_created(self, event):
        self.control = event.GetControl()
        event.Skip()

    def editor_shown(self, event):
        cursor = event.Row, event.Col
        value = self.grid1.GetCellValue(*cursor)
        if not value:
            self.grid1.SetCellValue(cursor[0], cursor[1], ' ')
            def unfix():
                self.control.SetValue(value)
                self.control.Popup()
                # @todo should set the cell value back to empty value here,
                # but that triggers the bug again.
            wx.CallAfter(unfix)
        event.Skip()


if __name__ == '__main__':
    app = wx.App()
    frame = Frame1(None)
    frame.Show(True)
    app.MainLoop()