Magnetic-moment operator of the relativistic electron

We consider for the Dirac electron the operator ${{→}}{m}=(1/2)e{{→}}{x}×{}{{•{}}{{→}}}{x}$ in the Heisenberg representation, and prove, by separating the center-of-mass coordinate ${{{→}}{x}}A$ and the relative coordinate ${{→}}{{ξ}}$ of the charge with respect to the center of mass (i.e., Zitterbewegung), that the orbital angular momentum of the Zitterbewegung is equal to the spin with the correct $g$ factor 2. The odd and even parts of ${{→}}{m}$ and the correct identification of the ${{→}}{L}$ and ${{→}}{S}$ operators are discussed.