svoid cleanDefunctACCsInAllThreads() {
  for (Thread t : allThreadsWithACC()) pcall {
    AccessControlContext acc = castGetOpt(t, 'inheritedAccessControlContext);
    if (acc == null) continue;
    L<S> defunctIDs = acc_defunctProgramIDs(acc);
    if (nempty(defunctIDs)) {
      S desc = threadGroupName(t) + " / " + t.getName();
      //print("DEFUNCT ACC IN THREAD! Cleaning. " + defunctIDs + ": " + desc);
      set(t, inheritedAccessControlContext := acc_current());
      //print("CLEANED.");
    }
  }
}