  Quantum field theories in front-form dynamics are not manifestly rotationally
invariant. We study a model bound-state equation in 3+1 dimensional front-form
dynamics, which was shown earlier to reproduce the Bohr and hyperfine structure
of positronium. We test this model with regard to its rotational symmetry and
find that rotational invariance is preserved to a high degree. Also, we find
and quantify the expected dependence on the cut-off.
