@Override
  public void fillFiles(Set<? super PsiFile> set, boolean recursively) {
    super.fillFiles(set, recursively);
    int count = getChildCount();
    Boolean isRoot = null;
    for (int i = 0; i < count; i++) {
      PackageDependenciesNode child = (PackageDependenciesNode)getChildAt(i);
      if (child instanceof FileNode || recursively) {
        child.fillFiles(set, true);
      }
      else if (child instanceof DirectoryNode) {
        if (isRoot == null) {
          isRoot = isContentOrSourceRoot();
        }
        if (isRoot) {
          child.fillFiles(set, false);
        }
      }
    }
  }
@Override
  public void fillFiles(Set<? super PsiFile> set, boolean recursively)