  A fully implicit particle-in-cell method for handling the
$v_\parallel$-formalism of electromagnetic gyrokinetics has been implemented in
XGC. By choosing the $v_\parallel$-formalism, we avoid introducing the
non-physical skin terms in Amp\`{e}re's law, which are responsible for the
well-known ``cancellation problem" in the $p_\parallel$-formalism. The
$v_\parallel$-formalism, however, is known to suffer from a numerical
instability when explicit time integration schemes are used due to the
appearance of a time derivative in the particle equations of motion from the
inductive component of the electric field. Here, using the conventional $\delta
f$ scheme, we demonstrate that our implicitly discretized algorithm can provide
numerically stable simulation results with accurate dispersive properties. We
verify the algorithm using a test case for shear Alfv\'{e}n wave propagation in
addition to a case demonstrating the ITG-KBM transition. The ITG-KBM transition
case is compared to results obtained from other $\delta f$ gyrokinetic
codes/schemes, whose verification has already been archived in the literature.
