code: public CompositeProgressMonitor addProgressMonitor(ProgressMonitor monitor) {
      this.monitors.add(monitor);
      monitor.addCancelListener(cancelListeners);
      return this;
    }
docs: Adds a <code>ProgressMonitor</code> to the collection.
  @param monitor The <code>ProgressMonitor</code> to add to the
  collection.
  @return This <code>CompositeProgressMonitor</code> is returns so that
  calls to this method may be chained.