Edge expand mask, Fair Positions/Tangency with multires modifier

When you press Shift A on the mesh border, expand mask by topology is drawn as offset of this border. Mesh border can be obtained by hiding the Face Set, but it doesn't work with multires modifier. It's strange why not. It would be convenient to make expand mask by topology border offset without hiding Face Set and make it in 2 directions. Also Fair Positions and Fair Tangency should also work with multires modifier