Get active window handle

static public HWND getActiveWhd()
{
    HWND                  AxClient, AxChild;
    ;

    AxClient = WinApi::findWindowEx(infolog.hWnd(), 0, "MDIClient", "");
    AxChild = WinApi::findWindowEx(AxClient, nullvalue(AxChild), "", ""); 
    return AxChild;
}