fixed wxFrame::IconizeChildFrames() bug which would restore the child frame even if it had been iconized before the main frame was

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@12407 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/frame.h

@@ -155,6 +155,9 @@ private:
     WXHWND                m_hwndToolTip;
 #endif // tooltips
 
+    // used by IconizeChildFrames(), see comments there
+    bool m_wasMinimized;
+
     DECLARE_EVENT_TABLE()
     DECLARE_DYNAMIC_CLASS(wxFrame)
 };