Compare file paths using wxFileName, not wxString, in the sample.

Compare file paths using wxFileName, not wxString, in the sample.

Comparing paths using wxString is a bad idea as identical paths can be seen as
mismatching because of case-only differences.

Also, don't reset wxRadioBox selection from its selection handler, this
doesn't work under e.g. wxGTK and is a bad example.

Closes #14791.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72820 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775