Apparently, wxConfigBase::Write() does not update values for next access on all platforms unless Flush() method is called. Added many calls to wxConfigBase::Flush() to make sure the Rad() calls get the right values.

src/prefs/MidiIOPrefs.cpp

@@ -271,7 +271,7 @@ bool MidiIOPrefs::Apply()
                                      wxString(info->name, wxConvLocal).c_str()));
    }
 #endif
-   return true;
+   return gPrefs->Flush();
 }
 
 bool MidiIOPrefs::Validate()