private CompositePackagingElement<?> getOrCreateModifiableRootElement(Artifact originalArtifact) {
    CompositePackagingElement<?> root = myModifiableRoots.get(originalArtifact);
    if (root == null) {
      root = ArtifactUtil.copyFromRoot(originalArtifact.getRootElement(), myProject);
      myModifiableRoots.put(originalArtifact, root);
    }
    return root;
  }
private CompositePackagingElement<?> getOrCreateModifiableRootElement(Artifact originalArtifact)