int getFilteredFilesCount() {
    Pair<PackageSetBase, NamedScopesHolder> scopeFilter = getScopeFilter();
    int[] result = new int[1];
    TreeUtil.traverse(myRoot, node -> {
      if (node instanceof FileTreeNode) {
        if (((FileTreeNode)node).acceptFilter(scopeFilter, true)) {
          result[0]++;
        }
      }
      return true;
    });
    return result[0];
  }
int getFilteredFilesCount()