private static boolean isVisible(@NotNull AnActionEvent event) {
    Project project = event.getProject();
    if (project == null || project.isDisposed()) return false;
    if (getVcsHelper(project) == null) return false;
    AbstractVcs vcs = getVcs(project, event.getData(VcsDataKeys.VCS));
    if (vcs == null) return false;
    VcsHistoryProvider vcsHistoryProvider = vcs.getVcsHistoryProvider();
    if (!(vcsHistoryProvider instanceof VcsHistoryProviderEx)) return false;
    return true;
  }
private static boolean isVisible(@NotNull AnActionEvent event)