Event on the DateTimeEditbox

<!-- editors:DateTimeEditBox -->
<Style x:Key="{x:Type editors:DateTimeEditBox}" TargetType="{x:Type editors:DateTimeEditBox}">
        <Trigger Property="DefaultDropDownContentType" Value="MonthCalendar">
            <Setter Property="DropDownContentTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <editors:MonthCalendar BorderThickness="0" ViewResetMode="FirstSelected"
                                SelectedDate="{Binding DateValue, RelativeSource={RelativeSource AncestorType={x:Type editors:DateTimeEditBox}}}"
                                Style="{Binding MonthCalendarStyle, RelativeSource={RelativeSource AncestorType={x:Type editors:DateTimeEditBox}}}"
                                editors:MonthCalendarDropDownBehavior.CloseOnClearSelection="True"
                                editors:MonthCalendarDropDownBehavior.CloseOnEscapeKey="True"
                                editors:MonthCalendarDropDownBehavior.CloseOnSingleSelection="True">
                            <editors:MonthCalendar.MaxDate>
                                <MultiBinding Converter="{StaticResource CoalesceConverter}">
                                    <Binding Path="Maximum"
                                            RelativeSource="{RelativeSource AncestorType={x:Type editors:DateTimeEditBox}}" />
                                    <Binding Source="{x:Static editors:DateTimeHelper.DefaultMaxDateTime}" />
                                </MultiBinding>
                            </editors:MonthCalendar.MaxDate>
                            <editors:MonthCalendar.MinDate>
                                <MultiBinding Converter="{StaticResource CoalesceConverter}">
                                    <Binding Path="Minimum"
                                            RelativeSource="{RelativeSource AncestorType={x:Type editors:DateTimeEditBox}}" />
                                    <Binding Source="{x:Static editors:DateTimeHelper.DefaultMinDateTime}" />
                                </MultiBinding>
                            </editors:MonthCalendar.MinDate>
                        </editors:MonthCalendar>
                    </DataTemplate>
                </Setter.Value>
            </Setter>
        </Trigger>
    </Style.Triggers>
</Style>