항상 위에 (TopMost)

 ::SetWindowPos(this->m_hWnd, HWND_TOPMOST, nX, nY, nWidth, nHeight, NULL);

함수를 사용하면된다

풀려면

 ::SetWindowPos(this->m_hWnd, HWND_NOTOPMOST, nX, nY, nWidth, nHeight, NULL);