DateTimePicker right click menu appearance

[gastonborba]

What steps will reproduce this issue?

The appearance of the context menu is not correct

Expected outcome

The context menu should be this way

Te code:
<Controls:DateTimePicker SelectedDate="{Binding DatePickerDate, Mode=TwoWay}" IsReadOnly="{Binding ReadOnly}" PickerVisibility="All" />

Environment

• MahApps.Metro v1.3.0-ALPHA137 (Prerelease)
• Windows 7
• Visual Studio 2013
• .NET Framework 4.5