messages do in fact retain the new subview properly. This is what the
documentation clearly states, and it checks out when looking at the
retainCount. I think I had been covering up a bug which I've since fixed.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@22638 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775