CallAfterとYield

積み残しだったYieldとCallAfterの調査。EventとしてPostされてますね。ということはYieldの中で処理されてしまいうるので、CallAfterで実行するメソッドがDlg::Destroyを呼ぶと落ちますね。これですっきり。気持ちよくねられます。
wxPython/src/_core_ex.py

def CallAfter(callable, *args, **kw):
    """
    Call the specified function after the current and pending event
    handlers have been completed.  This is also good for making GUI
    method calls from non-GUI threads.  Any extra positional or
    keyword args are passed on to the callable when it is called.

    :see: `wx.CallLater`
    """
    app = wx.GetApp()
    assert app is not None, 'No wx.App created yet'

    if not hasattr(app, "_CallAfterId"):
        app._CallAfterId = wx.NewEventType()
        app.Connect(-1, -1, app._CallAfterId,
                    lambda event: event.callable(*event.args, **event.kw) )
    evt = wx.PyEvent()
    evt.SetEventType(app._CallAfterId)
    evt.callable = callable
    evt.args = args
    evt.kw = kw
    wx.PostEvent(app, evt)