Thread memory leak

1) I have an ATL exe server ( Freethraded) and SimpleCOM client object in
it.

When Client is opened it starts a thread ... like this:

unsigned int WINAPI _ThrRoutine( LPVOID lpParam )
{
    return 0;
}

CClient::CClient()
{
    HANDLE hT = (HANDLE) _beginthreadex( NULL, 0, _ThrRoutine, NULL, 0,
NULL );
    WaitForSingleObject( hT, INFINITE );
    CloseHandle( hT );
}

2) Now I have a client program, opening and closing the CClient object in a
loop. (local computer, CoInitializeEx( NULL, COINT_MULTITHREADED )

HRESULT hr = piClient.CoCreateInstance( __uuidof( ClientObj ) );

and after some time

piClient.Release();

3) everything is OK, when I watch the memory for the server - it is stable,
not increasing ...

4) Now I just open a simple window in the server, one time at the beginning,
.... the window is doing nothing ...

HRESULT PreMessageLoop(int nCmdShow)
{
    HRESULT hr;
    hr = CAtlExeModuleT< CThrTestModule >::PreMessageLoop(nCmdShow);

    HWND hW = CreateWindow( L"EDIT", L"aaa", WS_POPUP, 100, 400, 100, 100,
NULL, NULL,
                                ::GetModuleHandle(NULL), NULL );

    ShowWindow( hW, SW_SHOW );

return S_OK;
}

5) now, every creating-terminating the Thread, makes some memory leak ( I
guess about 100 bytes each time ).
The consumption of memory is going up ... It should lead to crash ...

Does anybody know, what is the problem ?
thx
Antonin