Кнопка "закрыть" срабатывает со второго клика

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_LBUTTONDBLCLK:
        {
        DestroyWindow(hwnd);
        }
        break;
        case WM_CLOSE:
        {
        DestroyWindow(hwnd);
        }
        break;
        case WM_DESTROY:
        {
        PostQuitMessage(0);
        }
        break;
        default:
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}
//---------------------------------------------------------------------------
int __fastcall wnd()
{
hInstance = GetModuleHandle(NULL);
 
WNDCLASSEX WndClassStruct;
 
const wchar_t *WndClassName = L"MyWnd";
 
WNDCLASSEX CheckClassStruct;
    if(GetClassInfoEx(hInstance, WndClassName, &CheckClassStruct) == 0)
    {
    ZeroMemory(&WndClassStruct, sizeof(WNDCLASSEX));
    WndClassStruct.style = CS_CLASSDC | CS_DBLCLKS;
    WndClassStruct.cbSize = sizeof(WNDCLASSEX);
    WndClassStruct.lpfnWndProc = WndProc;
    WndClassStruct.cbClsExtra = 0;
    WndClassStruct.cbWndExtra = 0;
    WndClassStruct.hInstance = hInstance;
    WndClassStruct.hIcon = NULL;
    WndClassStruct.hCursor = LoadCursor(NULL, IDC_ARROW);
    WndClassStruct.hbrBackground = (HBRUSH)(COLOR_WINDOW);
    WndClassStruct.lpszMenuName = NULL;
    WndClassStruct.lpszClassName = WndClassName;
 
        if (!RegisterClassEx(&WndClassStruct))
        {
        return 0;
        }
    }
 
WndHwnd = CreateWindowEx(WS_EX_TOOLWINDOW, WndClassName, L"MyWndName", WS_OVERLAPPED | WS_VISIBLE, 0, 0, 200, 200, NULL, NULL, hInstance, NULL);
 
UpdateWindow(WndHwnd);
 
MSG Msg;
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
return Msg.wParam;
}