fixed locking problem

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@1910 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/thread/test.cpp

@@ -139,11 +139,11 @@ MyThread::MyThread(MyFrame *frame)
 void MyThread::WriteText(const wxString& text)
 {
     wxString msg;
-    msg << wxTime().FormatTime() << ": " << text;
 
     // before doing any GUI calls we must ensure that this thread is the only
     // one doing it!
     wxMutexGuiLocker guiLocker;
+    msg << wxTime().FormatTime() << ": " << text;
 
     m_frame->WriteText(msg);
 }