title: Changing the month in MonthCalendar fires DateChanged event twice
body: <p>Heyo, </p>
  
  <p>I have a standard WinForms MonthCalendar in my application with a handler hooked up to the DateChanged event. Whenever I change the date by day, clicking on a certain date in the little calendar, the event fires once. However, whenever I change the date by month, clicking on the &lt; and > in the control, the event fires twice. I want the event to fire once in all situations.</p>
  
  <p>Any ideas?</p>
  
  <p>EDIT: I debugged and found out that the SelectedItem or Range is the same on the first and second handler call. So I need a way to differentiate between the first and second call while still allowing for proper handling when the event only fires once.</p>
  
  <p>The handler code was requested, here it is, but it has nothing to do with the event firing multiple times:</p>
  
  <pre><code>List&lt;TimestampInfo&gt; displayTimestamps = databaseManger.QueryForTimestamps(DayPicker.SelectionRange);
  if (displayTimestamps == null) return;
  TimestampsListBox.Items.Clear();
  TimestampsListBox.Items.AddRange(displayTimestamps.ToArray());
  </code></pre>