message: consider BB atoms as trace
diff: @@ -291,7 +291,7 @@ export function isH(atomicNumber: ArrayLike<number>, element: ElementIndex) {
  export function isTrace(unit: Unit, element: ElementIndex) {
  if (Unit.isCoarse(unit)) return true;
  const atomId = unit.model.atomicHierarchy.atoms.label_atom_id.value(element);
  - if (atomId === 'CA' || atomId === 'P') return true;
  + if (atomId === 'CA' || atomId === 'BB' || atomId === 'P') return true;
  return false;
  }
  