# File lib/sup/modes/thread-index-mode.rb, line 447
  def multi_toggle_deleted threads
    undos = threads.map { |t| actually_toggle_deleted t }
    UndoManager.register "deleting/undeleting #{threads.size.pluralize 'thread'}",
                         undos, lambda { regen_text }, lambda { threads.each { |t| Index.save_thread t } }
    regen_text
    threads.each { |t| Index.save_thread t }
  end