IDirect3DStateBlock9 problem...

My problem is simple... if I define a stateblock using BeginStateBlock(...) and EndStateBlock(...), when I come to release the D3D device, it's reference count in non-zero; i.e. the stateblock does not release properly. If I use ->Capture(...) for the stateblock, it releases OK and the D3D device reference count is zero. I have included the following code to illustrate the problem. Am I doing something wrong?

/**//**//**//**//**//**//**//**//**//**//**//**//**//**//**//**///

#define WIN32_LEAN_AND_MEAN

// include

#include "resource.h"

#include "windows.h"

#include "winuser.h"
#include "stdio.h"
#include "stdlib.h"
#include "shlwapi.h"
#include "shellapi.h"

#define D3D_DEBUG_INFO

#include <D3D9.h>
#include <D3D9Types.h>
#include <d3dx9mesh.h>
#include <d3dx9core.h>

/**//**//**//**//**//**//**//**//**//**//**//**//**//**//**//**///

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
	HWND hwnd = CreateDialog(hInstance, MAKEINTRESOURCE(IDD_MAIN), NULL, NULL);
	if (hwnd == NULL)
	{
		MessageBox(NULL, "FAILED: CreateDialog()", "stateblock test", MB_OK);
		return false;
	}

	IDirect3D9				*pD3D			= NULL;
	IDirect3DDevice9		*pD3DDevice		= NULL;
	IDirect3DStateBlock9	*dwSB = NULL;

	if((pD3D = Direct3DCreate9(D3D_SDK_VERSION)) == NULL)
	{
		pD3D = NULL;
		MessageBox(hwnd, "FAILED: Direct3DCreate9()", "stateblock test", MB_OK);
		return false;
	}

	D3DPRESENT_PARAMETERS				d3dpp;
	ZeroMemory(&d3dpp, sizeof(D3DPRESENT_PARAMETERS));

	d3dpp.BackBufferWidth				= 32;
	d3dpp.BackBufferHeight				= 32;
	d3dpp.BackBufferFormat				= D3DFMT_A8R8G8B8;
	d3dpp.BackBufferCount				= 0;
	d3dpp.MultiSampleType				= D3DMULTISAMPLE_NONE;
	d3dpp.SwapEffect					= D3DSWAPEFFECT_DISCARD;
	d3dpp.hDeviceWindow					= hwnd;
	d3dpp.Windowed						= true;
	d3dpp.EnableAutoDepthStencil		= true;
	d3dpp.FullScreen_RefreshRateInHz	= D3DPRESENT_RATE_DEFAULT;
	d3dpp.PresentationInterval			= D3DPRESENT_INTERVAL_DEFAULT;
	d3dpp.AutoDepthStencilFormat		= D3DFMT_D16;

	DWORD dwVertexProcessing;

	//dwVertexProcessing = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
	dwVertexProcessing = D3DCREATE_MIXED_VERTEXPROCESSING;

	if (FAILED (pD3D->CreateDevice(
						D3DADAPTER_DEFAULT, 
						D3DDEVTYPE_HAL, 
						hwnd,
						dwVertexProcessing,
						&d3dpp, 
						&pD3DDevice
						)))
	{
		pD3DDevice = NULL;
		MessageBox(hwnd, "FAILED: CreateDevice()", "stateblock test", MB_OK);
		pD3D->Release();
		return false;
	}
	
	if (D3D_OK != (pD3DDevice->CreateStateBlock(D3DSBT_ALL, &dwSB)))
	{
		dwSB = NULL;
		MessageBox(hwnd, "FAILED: CreateStateBlock()", "stateblock test", MB_OK);
		pD3DDevice->Release();
		pD3D->Release();
		return false;
	}

	if (D3D_OK != (pD3DDevice->BeginStateBlock()))
	{
		MessageBox(hwnd, "FAILED: BeginStateBlock()", "stateblock test", MB_OK);
		dwSB->Release();
		pD3DDevice->Release();
		pD3D->Release();
		return false;
	}

	// Do SB stuff here

	if (D3D_OK != (pD3DDevice->EndStateBlock(&dwSB)))
	{
		MessageBox(hwnd, "FAILED: EndStateBlock()", "stateblock test", MB_OK);
		dwSB->Release();
		pD3DDevice->Release();
		pD3D->Release();
		return false;
	}

	dwSB->Release();
	DWORD dwRefCount = pD3DDevice->Release();
	pD3D->Release();

	char szM[1024];
	sprintf(szM, "dwRefCount = %ld", dwRefCount);
	MessageBox(hwnd, szM, "stateblock test", MB_OK);

	DestroyWindow(hwnd);
	EndDialog(hwnd, 0);

	return true;
}