Bug1329: not wholly satisfactory fix...

... Partial reversion of commit 2e8ee5fe75

Now, if you open an effect dialog, Return key will apply it.  But, if you
cycle among windows with alt+f6, then the focus moves among the controls in
the effect dialog, and I don't know how to prevent that.

At least so it is in Mac.  I have not verified it with Linux.

src/AudacityApp.cpp

@@ -1143,6 +1143,7 @@ int AudacityApp::FilterEvent(wxEvent & event)
       {
          const auto window = ((wxWindow *)e.GetEventObject());
          window->SetFocus();
+         window->NavigateIn();
       }
    }
 #endif