DateTimePicker select date bug

[xceedsoftware]

wizzard2012[CodePlex]
When I try to use DateTimePicker from Extended Wpf Toolkit I found this strange behaviour.
If I set up time any value differs from 0:00 and then try to select day in the next month

calendar skip this month and go to the next.
For example, if I try select date November 8, 2015 selected date will be December 6, 2015.
We have two changes (current month is October): one in November and one in Decmber.

It happend becouse date changing twice: one time when mouse down occurs and one when occurs mouse up. The result view is:

In the text field we see the correct month,

but in the calendar view there is December.

What can I do?

[xceedsoftware]

BoucherS[CodePlex]
This issue will be fixed in v2.2.

[xceedsoftware]

wizzard2012[CodePlex]
I found how to overcome this bug!
private bool _isMouseDown; //mouse button is pressed

public override void OnApplyTemplate()
{
base.OnApplyTemplate();

if( _popup != null )
_popup.Opened -= Popup_Opened;

_popup = GetTemplateChild( PART_Popup ) as Popup;

if( _popup != null )
_popup.Opened += Popup_Opened;

if (_calendar != null)
{
_calendar.SelectedDatesChanged -= Calendar_SelectedDatesChanged;
_calendar.PreviewMouseDown -= Calendar_PreviewMouseDown;
_calendar.PreviewMouseUp -= Calendar_PreviewMouseUp;
}

_calendar = GetTemplateChild( PART_Calendar ) as Calendar;

if( _calendar != null )
{
_calendar.SelectedDatesChanged += Calendar_SelectedDatesChanged;
_calendar.PreviewMouseDown += new MouseButtonEventHandler(Calendar_PreviewMouseDown);
_calendar.PreviewMouseUp += new MouseButtonEventHandler(Calendar_PreviewMouseUp);
_calendar.SelectedDate = Value ?? null;
_calendar.DisplayDate = Value ?? DateTime.Now;
}

_timePicker = GetTemplateChild( PART_TimeUpDown ) as TimePicker;
}

void Calendar_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
_isMouseDown = true;
}

void Calendar_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
_isMouseDown = false;
}

protected override void OnValueChanged( DateTime? oldValue, DateTime? newValue )
{
if( _calendar != null _calendar.SelectedDate != newValue )
{
_calendar.SelectedDate = newValue;
if (!_isMouseDown) // we do not need to update dispay if mouse is pressed
_calendar.DisplayDate = newValue ?? DateTime.Now;
}

base.OnValueChanged( oldValue, newValue );
}

[xceedsoftware]

wizzard2012[CodePlex]
the bug is here
protected override void OnValueChanged( DateTime? oldValue, DateTime? newValue )
{
if( _calendar != null _calendar.SelectedDate != newValue )
{
_calendar.SelectedDate = newValue;
_calendar.DisplayDate = newValue; // see coments later
}

base.OnValueChanged( oldValue, newValue );
}

and here
private void Calendar_SelectedDatesChanged( object sender, SelectionChangedEventArgs e )
{
if( e.AddedItems.Count 0 )
{
var newDate = ( DateTime? )e.AddedItems[ 0 ];

if( ( Value != null )  ( newDate != null )  newDate.HasValue )
{
  // Only change the year, month, and day part of the value. Keep everything to the last tick.
  // Milliseconds aren't precise enough. Use a mathematical scheme instead.
  newDate = newDate.Value.Date + Value.Value.TimeOfDay;
}

if( !object.Equals( newDate, Value ) )
  Value = newDate;

}
}

When user clicks on grayed date SelectedDatesChanged occurs. It change Value member of control.
And thus OnValueChanged event handler works. Then
_calendar.DisplayDate
assign new value to display date for swich to correct month. But now, inside calendar OnDisplayDateChanged event ocurs, which overdraw month pane. And when user release mouse button Cell_MouseUp event occurs in calendar that updates calendar again.
The workaround is to modify UpDown control to limit user in hours / minutes change.