WPF Datepicker Calendar Style Bug - wpf

Question

I am developing a WPF application and I'm using the standard WPF Datepicker.
Here is the XAML Code:
<DatePicker Grid.Column="0" Grid.Row="5" Margin="5,0,5,12"
x:Name="SendungDatePicker" SelectedDate="{Binding Path=ProduktionsDatum}"
ToolTip="{x:Static resx:MetaData.DateTooltip}" />
However, when I use it, the upper part of the calendar isn't displayed correctly:
As you can see, I can't see the month and year.
How can I solve this problem?
Thank you for your help
EDIT
I generated a template for the calendar style:
<Style x:Key="CalendarStyle1" TargetType="{x:Type Calendar}">
<Setter Property="Foreground" Value="#FF333333"/>
<Setter Property="Background">
<Setter.Value>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFE4EAF0" Offset="0"/>
<GradientStop Color="#FFECF0F4" Offset="0.16"/>
<GradientStop Color="#FFFCFCFD" Offset="0.16"/>
<GradientStop Color="White" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush">
<Setter.Value>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFA3AEB9" Offset="0"/>
<GradientStop Color="#FF8399A9" Offset="0.375"/>
<GradientStop Color="#FF718597" Offset="0.375"/>
<GradientStop Color="#FF617584" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Calendar}">
<StackPanel x:Name="PART_Root" HorizontalAlignment="Center">
<CalendarItem x:Name="PART_CalendarItem" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Style="{TemplateBinding CalendarItemStyle}" Height="Auto" Width="Auto"/>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
How can I update the height of the header of the calendar?

Answer 1

If you generate a style for CalendarItem then you will find that Height of Header Button is 20 and FontSize is 10.5. So you override the CalendarItem style and defined either the height of PART_HeaderTemplate or decrease the FontSize.
<Button x:Name="PART_PreviousButton" Grid.Column="0" Focusable="False" HorizontalAlignment="Left" Height="20" Grid.Row="0" Template="{StaticResource PreviousButtonTemplate}" Width="28"/>
<Button x:Name="PART_HeaderButton" Grid.Column="1" FontWeight="Bold" Focusable="False" FontSize="10.5" HorizontalAlignment="Center" Grid.Row="0" Template="{StaticResource HeaderButtonTemplate}" VerticalAlignment="Center"/>
<Button x:Name="PART_NextButton" Grid.Column="2" Focusable="False" HorizontalAlignment="Right" Height="20" Grid.Row="0" Template="{StaticResource NextButtonTemplate}" Width="28"/>

Answer 2

the problem is very simple, the header of your DatePicker is a Button. Surely you have somewhere put a style for your buttons where you specify a height for them.
Solution: if for your buttons you have set ... Height = 20 you must raise the height, Height = 25 Or try until you see that the header is not cut. That's why my friend cuts himself, because the button is not high enough.
I hope this helps someone who ever has this problem, since it's something that drove me crazy.