how to make double camera/window desktop meatio AR program

Question

I am developing AR things with Metaio. I have dual camera and trying to make dual opengl rendering window based on the MFC template project of metaio SDK.http://dev.metaio.com/sdk/documentation/first-app-running-template-on-each-platform/windows/index.html

I try to make double window and open different camera like:

firstly, window class holding MFC window and metaio SDK instance

class CMyWindow : public CFrameWnd, metaio::IMetaioSDKCallback
{
        CMyWindow();
        ~CMyWindow();

...
        metaio::IMetaioSDKWin32*    m_pMetaioSDK;
        metaio::ISensorsComponent*      m_sensors;
        metaio::GestureHandlerWindows* m_gestureHandler;
}

then a winApp class like:

    class CMyApplication : public CWinApp
{
public:
    virtual BOOL InitInstance();
}

in the InitInstance() method, I make up two window like:

BOOL CMyApplication::InitInstance() 
{
    // we have to call this right at the beginning
    AfxEnableControlContainer();

    // start the main windows, and init ARBrowser
    try
    {
    m_win = new CMyWindow;
        //get cameralist
        metaio::stlcompat::Vector<metaio::Camera> cameraList;
        cameraList = m_win->m_pMetaioSDK->getCameraList();
        //check whether there is two camera.
        assert( cameraList.size() == 2);
        //sync these two camera parameters
        for(int i = 0; i < cameraList.size(); i++)
        {
            metaio::Vector2di res = metaio::Vector2di(RES_WIDTH,RES_HEIGHT);
            cameraList[i].resolution = res;
        }
        //assert(cameraList[0] == cameraList[1]);
        m_win->m_pMetaioSDK->startCamera(cameraList[0]);

        m_pMainWnd = m_win;
        m_pMainWnd->ShowWindow( m_nCmdShow );


        //the other window
        m_win_right = new CMyWindow;
        m_win_right->m_pMetaioSDK->startCamera(cameraList[1]);
        m_pMainWnd = m_win_right;
        m_pMainWnd->ShowWindow( m_nCmdShow );
}catch( std::exception& e )
}

however, rendering is not working properly, I see two blank window. noticing that two camera is opened, I find the tracking status pops up things if reaching the pattern. I guess is the rendering problem. I would like to check the customized rendering part of metaio.

Any suggestions? Discussion welcome.