[Dev-C++] CreateMenu + InsertMenuItem

I have to create dynamically a menu from a file. From the win32
documentation and several web sites, I tried the following code, based
on InsertMenuItem. This function returns a nonzero value=3DOK, but no =
menu
is displayed. If I try a static menu with LoadMenu and SetMenu, instead
of this code, the menu is displayed correctly (but is static).
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What=92s wrong with this code ?=20
=20
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   HMENU hMyMenu=3DCreateMenu();
   if (!hMyMenu)
   {
      MessageBox(NULL, "Unable to create Menu", "Internal error", 0);
      return FALSE;
   }
   DWORD IDCurrentItem=3D1;
   int iPosition=3D0;
   while (<not end of file>) //it loops several times
   {
         char szBuffer[BUFFER_SIZE] ;
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         <read szBuffer from file> // the buffer content is OK
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         MENUITEMINFO NMI;
         ZeroMemory(&NMI, sizeof NMI);
         NMI.cbSize=3Dsizeof NMI;
         NMI.fMask=3DMIIM_STATE||MIIM_ID||MIIM_TYPE;
         NMI.fType=3DMFT_STRING;
         NMI.fState=3DMFS_ENABLED;
         NMI.wID=3DIDCurrentItem++;
         NMI.dwTypeData=3D(LPTSTR)szBuffer;
         NMI.cch=3Dstrlen(szBuffer);
         if (!InsertMenuItem(hMyMenu, iPosition++, TRUE, &NMI))
         {
            MessageBox(NULL, szBuffer, "Internal Error: unable to create
menu item=94, 0);
            return FALSE;
         }
   }
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   SetMenu(hwnd, hMyMenu); // no menu displayed !!
   return TRUE;