Why doesn't my code display the window under the desktop icons?

Question

I am writing a live wallpaper. So, first thing is create a window and set it behind the desktop icons. Now I almost finish it. I don't know why sometimes the icons display above the window, and most of the time the icons display behind the window.

My main codes is as follows.

I find the SHELLDLL_DefView window, and set my window be a child for it, then I set it HWND_BOTTOM.

glfwInit();
GLFWwindow* window = glfwCreateWindow(800, 600, "my window", NULL, NULL);
HWND hwnd = glfwGetWin32Window(window);

SetWallpaperWindowPosition(hwnd);

void SetWallpaperWindowPosition(HWND hwnd)
{
    auto r = GetSDDV();
    HWND SDDV = std::get<0>(r);
    HWND SLV32 = std::get<1>(r);
    HWND WorkerW = std::get<2>(r);

    SetParent(hwnd, SDDV);
    SetWindowLongPtr(hwnd, GWL_STYLE, WS_CHILD | WS_VISIBLE);
    SetWindowPos(hwnd, HWND_BOTTOM, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
}

BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
    std::tuple<HWND, HWND, HWND>* result = reinterpret_cast<std::tuple<HWND,HWND,HWND>*>(lParam);
    TCHAR szClassName[256];
    TCHAR szWindowName[256];

    GetClassName(hwnd, szClassName, _countof(szClassName));
    GetWindowText(hwnd, szWindowName, _countof(szWindowName));

    if (!_tcscmp(szClassName, _T("WorkerW")))
    {
        HWND SDDV = FindWindowEx(hwnd, NULL, _T("SHELLDLL_DefView"), NULL);
        if (SDDV)
        {
            HWND SLV32 = FindWindowEx(SDDV, NULL, _T("SysListView32"), _T("FolderView"));
            std::get<0>(*result) = SDDV;
            std::get<1>(*result) = SLV32;
            std::get<2>(*result) = hwnd;
            return FALSE;
        }
    }

    return TRUE; 
}

std::tuple<HWND, HWND, HWND> GetSDDV()
{
    std::tuple<HWND, HWND, HWND> P;
    EnumWindows(EnumWindowsProc, reinterpret_cast<LPARAM>(&P));

    return P;
}