CMDIFrameWnd and Create

Hi,

this code is not working,
why?

Code:

#include <afxwin.h>	
#include <afxtempl.h> 

#include "resource.h"


class CTestXApp : public CWinApp
{
	public:
	
	BOOL InitInstance()
	{	
		
		/// works with this: CFrameWnd* pMainFrame = new CFrameWnd; 

		CMDIFrameWnd* pMainFrame = new CMDIFrameWnd;

		m_pMainWnd = pMainFrame;
		pMainFrame->Create (NULL, "My App");		
		pMainFrame->ActivateFrame();

		return TRUE;
	}
};


CTestXApp theApp;

If executed, appears "Assertion Failed" message.

I really appreciate If somebody gives a little simple (very simple) sample of creating CMDIFrame and blank child windows.

I looked in winmdi.cpp and now I know why this "Assertion Failed" appears.
CMDIFrameWnd must have menu with submenu and at least with two items.

I made menu (resource) and called LoadFrame() method instead Create():

Code:

CMDIFrameWnd->LoadFrame(IDR_MYMENU);

Now it works.