@Override
    protected void appendChildrenTo(@NotNull final Collection<? super ConvenientNode> children) {
      Project project = getObject();
      VirtualFile[] roots = ProjectRootManager.getInstance(project).getContentRoots();

      NextRoot:
      for (VirtualFile root : roots) {
        for (VirtualFile candidate : roots) {
          if (VfsUtilCore.isAncestor(candidate, root, true)) continue NextRoot;
        }
        if (myFilter.accept(root)) {
          children.add(new FileNode(root, project, myFilter));
        }
      }
    }
@Override
    protected void appendChildrenTo(@NotNull final Collection<? super ConvenientNode> children)