For some reason acting on date in the way other than picking it from calendar doesn't change calendars view i.e. you open calendar and select current date (e.g. 25 Jul 2014). Then you change date manually e.g. using up down buttons or mouse wheel to e.g. 25 Jun 2000. Next time you open calendar you'll still see Jul 2014.
Maybe its not a bug but here is an example when it has bad visual experience: you have Value property of DateTimePicker bound to property in data context which is initially unset i.e. 1 Jan 0001. When you change the value of the property the date displayed is correct but when you open calendar you'll see Jan 0001 and you have fun time moving to something closer to present time
Comments: ** Comment from web user: jcCodePlex59 **
Maybe its not a bug but here is an example when it has bad visual experience: you have Value property of DateTimePicker bound to property in data context which is initially unset i.e. 1 Jan 0001. When you change the value of the property the date displayed is correct but when you open calendar you'll see Jan 0001 and you have fun time moving to something closer to present time
Comments: ** Comment from web user: jcCodePlex59 **
My last comment was a little harsh and I don't know how to change it. It's a very nice control, except for this one, very unfortunate bug.