@NotNull
    private static List<PropertiesFile> filterNotInLibrary(@NotNull Project project,
                                                           @NotNull List<? extends PropertiesFile> propertiesFiles) {
      final ProjectFileIndex fileIndex = ProjectRootManager.getInstance(project).getFileIndex();

      final List<PropertiesFile> result = new ArrayList<>(propertiesFiles.size());
      for (final PropertiesFile file : propertiesFiles) {
        if (!fileIndex.isInLibrary(file.getVirtualFile())) {
          result.add(file);
        }
      }
      return result;
    }
@NotNull
    private static List<PropertiesFile> filterNotInLibrary(@NotNull Project project,
                                                           @NotNull List<? extends PropertiesFile> propertiesFiles)