CS_SAVEBITS не отменяет WM_PAINT?

#include "stdafx.h"
#include "Win32Project1.h"
#include <string>
#include <sstream>
 
HINSTANCE hInst;
const WCHAR* szTitle = L"SAVEBITS Test";
const WCHAR* szWindowClass = L"SAVEBITS";
 
UINT Counter = 0;
const CHAR* CounterStr;
std::string Str;
std::stringstream out;
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
PAINTSTRUCT ps;
RECT rect;
HDC hdc;
HBRUSH hBrush;
 
    switch (message) {
        case WM_PAINT:
            hdc = BeginPaint(hWnd, &ps);
            hBrush = CreateSolidBrush(RGB(0, 255, 0));
            GetClientRect(hWnd, &rect);
            FillRect(hdc, &rect, hBrush);
            DeleteObject(hBrush);
            SetTextColor(hdc, RGB(255, 255, 255));
            SetBkMode(hdc, TRANSPARENT);
            out << ++Counter;
            Str = out.str();
            CounterStr = Str.c_str();
            DrawTextA(hdc, (LPCSTR) CounterStr, -1, &rect, DT_CENTER + DT_VCENTER + DT_SINGLELINE);
            EndPaint(hWnd, &ps);
            SetWindowTextA(hWnd, (LPCSTR) CounterStr);
            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}
 
ATOM MyRegisterClass(HINSTANCE hInstance) {
    WNDCLASSEXW wcex;
 
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW | CS_SAVEBITS;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WIN32PROJECT1));
    wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground = nullptr;
    wcex.lpszMenuName = nullptr;
    wcex.lpszClassName = szWindowClass;
    wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
 
    return RegisterClassExW(&wcex);
}
 
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow) {
 
    hInst = hInstance;
 
    HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
                                               CW_USEDEFAULT, 0,
                                               CW_USEDEFAULT, 0,
                                               nullptr, nullptr, hInstance, nullptr);
 
   if (!hWnd) return FALSE;
 
   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);
 
   return TRUE;
}
 
 
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                                _In_opt_ HINSTANCE hPrevInstance,
                                _In_ LPWSTR lpCmdLine,
                                _In_ int nCmdShow)
{
    MSG msg;
 
    if (MyRegisterClass(hInstance) && InitInstance (hInstance, nCmdShow)) {
        while (GetMessage(&msg, nullptr, 0, 0)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
 
    return (int) msg.wParam;
}