Possible fix for DestroyWindow message in MDI apps (call DestroyChildren in destructor)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@6719 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/mdi.cpp

@@ -705,6 +705,12 @@ bool wxMDIChildFrame::Create(wxMDIParentFrame *parent,
 
 wxMDIChildFrame::~wxMDIChildFrame()
 {
+    DestroyChildren();
+
+    // already delete by DestroyChildren()
+    m_frameToolBar = NULL;
+    m_frameStatusBar = NULL;
+
     MSWDestroyWindow();
 }