Linker error for CSingleWorkspace

I need to provide my own implementation for CSingleWorkspace. With the following code;

#define _XTP_STATICLINK
#include "XTCommandBarsPro.h"

class CMyTabClientWnd : public CXTPTabClientWnd
{
public:
     class CMyWorkspace : public CXTPTabClientWnd::CSingleWorkspace
     {};

public:
     virtual CWorkspace* CreateWorkspace()
     {
          return new CMyWorkspace();
     }
};

I get the following 4 linker errors;

MyTabClientWnd.obj : error LNK2001: unresolved external symbol "protected: virtual class ATL::CStringT<unsigned short,class StrTraitMFC_DLL<unsigned short,class ATL::ChTraitsCRT<unsigned short> > > __thiscall CXTPTabClientWnd::GetItemText(class CWnd const *)const " (?GetItemText@CXTPTabClientWnd@@MBE?AV?$CStringT@GV?$StrTraitMFC_DLL@GV?$ChTraitsCRT@G@ATL@@@@@ATL@@PBVCWnd@@@Z)

Using MFC in a shared DLL, and linking to CodeJock as a static lib. Any ideas how to resolve this?

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