message: Continue rendering instead of return, as suggested by Marc
diff: @@ -364,8 +364,7 @@ void Cartoons::process(const Molecule& molecule, Rendering::GroupNode& node)
  backbones = getBackboneByResidues(molecule, layer);
  }
  if (backbones.size() == 0) {
  - return;
  - // backbones = getBackboneManually(molecule, layer);
  + continue; // maybe something in a different layer
  }
  size_t i = 0;
  for (const auto& group : backbones) {
  