private static @NotNull String getOrCreateContentId(@NotNull Content content) {
    @NonNls String id = content.getUserData(ViewImpl.ID);
    if (id == null) {
      id = "UnknownView-" + content.getDisplayName();
      content.putUserData(ViewImpl.ID, id);
    }
    return id;
  }
private static @NotNull String getOrCreateContentId(@NotNull Content content)