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?
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?