[C++] GDI+ Create Controls

Hay everybody,
i want to create a splash screen window but got one Problem.
I already displayed my Bitmap with UpdateLayeredWindow and alpha blend,
but if i try to create a Control on it, it doesn't show anything.
here is a screen of the Window.
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and here my Winmain.

Code:

    Gdiplus::GdiplusStartupInput gdiplusStartupInput;
    Gdiplus::GdiplusStartup(&m_gdiplusToken, &gdiplusStartupInput, NULL);
    hBmp = LoadBitmap(hinst, MAKEINTRESOURCE(IDB_SPLASH));
	
    WNDCLASSEX wcex;

    wcex.cbSize          = sizeof(WNDCLASSEX);
    wcex.style           = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
    wcex.lpfnWndProc     = WndProc;
    wcex.cbClsExtra      = 0;
    wcex.cbWndExtra      = 8; // 8 bytes, to allow for 64-bit architecture
    wcex.hInstance       = hinst; // CHECK
    wcex.hIcon           = NULL;
    wcex.hCursor         = ::LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground   = (HBRUSH)NULL_BRUSH; // CHECK
    wcex.lpszMenuName    = NULL;
    wcex.lpszClassName	 = "GDI_Window";
    wcex.hIconSm         = NULL;
	
    RegisterClassEx(&wcex);

    HWND wnd = CreateWindowEx(WS_EX_TOPMOST | WS_EX_LAYERED, "GDI_Window", "Projectx7 Kickhack v4", WS_POPUP , 0, 0, 700, 500, NULL, NULL, hinst, NULL);
	
	Blend(wnd, hBmp, 255);
	ShowWindow(wnd, nShowCmd);
	UpdateWindow(wnd);

	MSG msg = { 0 };

    while ( ::GetMessage( &msg, NULL, 0, 0 ) )
    {
            ::TranslateMessage(&msg);
            ::DispatchMessage(&msg);
    }

    Gdiplus::GdiplusShutdown(m_gdiplusToken);