title: Why do notifications make opening another activity instance?
body: <p>I have an activity which starts a service through a button press. During service initialization, if an error occurs, this error is displayed by a notification, as follows:</p>
  
  <pre><code>String tickerText = getString(R.string.init_error);
  
  Notification notification = new Notification(
          R.drawable.ic_stat_notify_msg,
          tickerText, System.currentTimeMillis());
  
  PendingIntent notificationIntent = PendingIntent.getActivity(
          this, 0, new Intent(this, MyServiceActivity.class), 0);
  
  notification.setLatestEventInfo(this,
          getText(R.string.init_error_tts_title),
          getText(R.string.init_error_tts_text),
          notificationIntent);
  
  NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
  nm.notify(R.string.init_error, notification);
  
  stopSelf();
  </code></pre>
  
  <p>When the notification appears in the status bar, I open the notifications window. Then, when I click on the notification, a new instance of MyServiceActivity is launched... Why?</p>