agw.aui.AuiNotebook not unsplitting if pages have children

I used SetSashDClickUnsplit to switch on unsplitting for an agw.aui.AuiNotebook, but double-clicking on the sash had no effect. After some digging around in the code I found this seemed to be because my notebook pages have children so the notebook may need to look for an ancestor.
Overriding the GetTabFrameFromWindow method seems to have fixed things - I added the following at the start of the method to find the direct child of the notebook:

    while wnd.GetParent() != self:
        wnd = wnd.GetParent()

Does this seem reasonable? I’m using wxPython with Python 2.7 (Windows 7 and Centos 7) but the Phoenix code doesn’t appear to have changed.

Please create a PR with the change, and a simple example that replicates the problem, and somebody will take a closer look.