Commented Unassigned: DateTimePicker crash [21963]

```
A first chance exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll

Additional information: 'Set property 'Xceed.Wpf.Toolkit.Primitives.UpDownBase(System.Nullable(System.DateTime)).Value' threw an exception.' Line number '68' and line position '37'.
```
---
Attemping to use DateTimePicker, or any of the DateTime* causes it to crash.
Any form for parameters cause the same to happen.

---
Tried install the Toolkit Plus edition, and then i did not get the error.
Comments: ** Comment from web user: Spuriga **

I have the same problem with xctk 3.0.0, Visual Studio 2015 and Windows 8.1, and .NET 4.5.1.

If Format="Custom" the exception appears, if anything else, it is ok.
```
<xctk:DateTimePicker Value="{Binding FilterFromDate}"
Format="Custom"
FormatString="yyyy.MM.dd HH:mm"
ShowButtonSpinner="False"
Margin="0,5,0,0"
HorizontalAlignment="Center"/>
```
and set the "FilterFromDate" bound property from code behind in the model constructor.

In the model:
```
public DateTime? FilterFromDate
{
get { return this._filterFromDate; }
set
{
this._filterFromDate = value;
this.NotifyPropertyChanged();
}
}
```
Constructor:
```
this.FilterFromDate = new DateTime?(DateTime.Now.AddHours(-12));
```