title: Picking photo from Photochooser or holding hardware back button cause active timers ring
body: <p>This is a very strange problem, and all the people I had asked to confirm it said that it takes place.</p>
  
  <p>I have a <code>Threading.Timer</code> instance which fires every 15 minutes. And if I call the <code>PhotoChooser</code> view and then select a photo from it, when going back to the calling page my application calls that timer's callback! I tried different timers either it be Timer from Threading namespace or Dispatcher timer.</p>
  
  <p>The same happens when being in my app I hold the back button of my device and then choose the app from the list.</p>
  
  <p>My application is as plain as it can be - the timer with a callback and method calling PhotoChooser. Could anyone help with solution or workaround please?</p>
  
  <p><strong>Update:</strong></p>
  
  <p>My code construction is as follows:</p>
  
  <pre><code>private Timer _timer;
  
  public void CallTimer()
  {
      var period = 15 * 1000 * 60;
     _timer = new Timer(repeatTimer_Tick, null, 0, period);
  }
  
  private void repeatTimer_Tick(object state)
  {
     // Some action here
  }
  
  private void Stop()
  {
     if (_timer != null)
       _timer.Dispose();
  }
  
  private void CallPhotoChooser()
  {
     // Some basic actions calling photochooser task
  }
  </code></pre>