Validation Error Template Adorner is cut insight a ScrollViewer - wpf

Question

i have the following problem. as far a i put my Textboxes in a scrollviewer my ValidationError Adorner get cut by the ScrollViewer. i found some answers to Adorner and ScrollViewer which say i need to retemplate my scrollviewer and add an adornerdecorator. but this makes no sense to me and it doesnt help either.
as far as i know should the Validation Adorner rendered in the nearest AdornerDecorator. the ScrollViewer by default has no AdornerDecorator. so does anybody know why my ValidationAdorner get cut?
I also looking for a solution :)
EDIT: it seems the ScrollContentPresenter which comes from the ScrollViewer Template cause the problem, because it has a AdornerLayer by default. Any ideas how to solve my issue?
EDIT2:
is there a way to create a new ScrollConntentPresenter Template without a Adornerlayer?
or is there a way to remove a the Adornerlayer from the VisualTree?
or can i force the Adornerlayer to render in a" higher/most top" AdornerLayer?
or can i have Scrolling Content without a ScrollViewer?
here is my xaml:
<UserControl>
<AdornerDecorator>
<Grid x:Name="RootControl">
<Grid.RowDefinitions>
<RowDefinition Height="auto" MinHeight="50"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid x:Name="main" Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Border x:Name="InputBorder" Grid.Column="0">
<ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
<Grid x:Name="InputContainer" HorizontalAlignment="Stretch">
<Grid.RowDefinitions>
...some rows...
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
...some columns...
</Grid.ColumnDefinitions>
<TextBox .../><!--this Validation Adorner get cut by scrollviewer-->
</Grid>
</ScrollViewer>
</Border>
</Grid>
</Grid>
</AdornerDecorator>
</UserControl>
here is my Validation Template:
<ControlTemplate x:Key="ValidationTemplate" >
<DockPanel>
<AdornedElementPlaceholder Name="MyAdornedElement" />
<Grid>
<Border Background="{StaticResource BrushError}" Margin="3,0,0,0" x:Name="ErrorControl" BorderBrush="White" BorderThickness="1">
<TextBlock Margin="10,3,5,2"
Text="{Binding ElementName=MyAdornedElement,Path=AdornedElement.(Validation.Errors).CurrentItem.ErrorContent}"
Visibility="{Binding ElementName=MyAdornedElement,Path=AdornedElement.Visibility}"
Foreground="White" FontWeight="Bold">
</TextBlock>
</Border>
<Path x:Name="path" Margin="3,0,0,0" Data="M 0,10 L 10,0 " Fill="{StaticResource BrushError}"
StrokeThickness="2" Stroke="White"
/>
</Grid>
</DockPanel>
</ControlTemplate>

Answer 1

the behavior is intended. A ScrollViewer is able to hide some of it's contents (ie the content lying in the extent). Showing an Adorner for such content that doesn't get clipped, results in a strange UI.
What you should be able to do in the ValidationTemplate though is putting the Grid element inside a Popup control. Please try that and report if it worked.