compilation fix + comment about bogus memory leak (patch 1849988)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@50707 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/mfc/mfctest.cpp

@@ -38,8 +38,17 @@
 //
 //     nmake -f makefile.vc BUILD=debug SHARED=0 DEBUG_RUNTIME_LIBS=0 RUNTIME_LIBS=static all
 //
-//     Unless the run-time library settings match for wxWidgets and MFC, you will get
-//     link errors for symbols such as __mbctype, __argc, and __argv 
+//     Unless the run-time library settings match for wxWidgets and MFC, you
+//     will get link errors for symbols such as __mbctype, __argc, and __argv 
+//
+// (3) If you see bogus memory leaks within the MSVC IDE on exit, in this
+//     sample or in your own project, you must be using __WXDEBUG__ +
+//     WXUSINGDLL + _AFXDLL
+//     Unfortunately this confuses the MSVC/MFC leak detector. To do away with
+//     these bogus memory leaks, add this to the list of link objects, make it
+//     first: mfc[version][u]d.lib
+//     -  [version] -> 42 or 70 or 80 etc
+//     -  u if using Unicode
 
 #include "stdafx.h"
 
@@ -214,7 +223,8 @@ int CTheApp::ExitInstance()
 // Override this to provide wxWidgets message loop compatibility
 BOOL CTheApp::PreTranslateMessage(MSG *msg)
 {
-    wxEventLoop *evtLoop = wxEventLoop::GetActive();
+    wxEventLoop * const
+        evtLoop = wx_static_cast(wxEventLoop *, wxEventLoop::GetActive());
     if ( evtLoop && evtLoop->PreProcessMessage(msg) )
         return TRUE;