Applied patch #1198401(GroupBox background painting cure).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@34058 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/os2/window.cpp

@@ -394,6 +394,10 @@ bool wxWindowOS2::Create(
                   _T("wxStaticBox can't be used as a window parent!") );
 #endif // wxUSE_STATBOX
 
+     // Ensure groupbox backgrounds are painted
+     if (IsKindOf(CLASSINFO(wxPanel)))
+         lStyle &= ~wxCLIP_CHILDREN;
+
     if ( !CreateBase( pParent
                      ,vId
                      ,rPos