ItemsPresenter crashes XAML designer - wpf

Question

I have the following TreeView in my Windows XAML
<TreeView Margin="3" ItemsSource="{Binding Path=Model.Files}"
TreeViewItem.Collapsed="TreeViewItem_OnCollapsed">
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<Setter Property="IsExpanded" Value="{Binding Path=IsExpanded}" />
<Setter Property="IsSelected" Value="{Binding Path=IsSelected}" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" MinWidth="19" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ToggleButton IsChecked="False" Visibility="Hidden"
ClickMode="Press" Name="Expander" />
<Border
BorderThickness="{TemplateBinding Border.BorderThickness}"
Padding="{TemplateBinding Control.Padding}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
Background="{TemplateBinding Panel.Background}" Name="Bd"
SnapsToDevicePixels="True" Grid.Row="0" Grid.Column="1">
<ContentPresenter
Content="{TemplateBinding HeaderedContentControl.Header}"
ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}"
ContentStringFormat="{TemplateBinding HeaderedItemsControl.HeaderStringFormat}"
ContentSource="Header" Name="PART_Header"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
<ItemsPresenter Name="ItemsHost" Grid.Column="1" Grid.Row="1"
Grid.ColumnSpan="2" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="ItemsControl.HasItems">
<Setter Property="UIElement.Visibility"
TargetName="Expander">
<Setter.Value>
<x:Static Member="Visibility.Hidden" />
</Setter.Value>
</Setter>
<Trigger.Value>
<system:Boolean>False</system:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="TreeViewItem.IsSelected">
<Setter Property="Panel.Background" TargetName="Bd">
<Setter.Value>
<DynamicResource
ResourceKey="{x:Static SystemColors.HighlightBrushKey}" />
</Setter.Value>
</Setter>
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource
ResourceKey="{x:Static SystemColors.HighlightTextBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<system:Boolean>True</system:Boolean>
</Trigger.Value>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected">
<Condition.Value>
<system:Boolean>True</system:Boolean>
</Condition.Value>
</Condition>
<Condition Property="Selector.IsSelectionActive">
<Condition.Value>
<system:Boolean>False</system:Boolean>
</Condition.Value>
</Condition>
</MultiTrigger.Conditions>
<Setter Property="Panel.Background" TargetName="Bd">
<Setter.Value>
<DynamicResource
ResourceKey="{x:Static SystemColors.ControlBrushKey}" />
</Setter.Value>
</Setter>
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource
ResourceKey="{x:Static SystemColors.ControlTextBrushKey}" />
</Setter.Value>
</Setter>
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled">
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource
ResourceKey="{x:Static SystemColors.GrayTextBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<system:Boolean>False</system:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate DataType="{x:Type models:FileData}"
ItemsSource="{Binding Path=Files}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Rectangle x:Name="Rect" Grid.Column="0" Width="15" Height="15" Margin="3"
Fill="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=TreeViewItem}, Path=Foreground}">
<Rectangle.OpacityMask>
<VisualBrush Stretch="Fill">
<VisualBrush.Visual>
<MultiBinding Converter="{StaticResource MultiToVisual}">
<Binding Path="." />
<Binding Mode="OneWay"
Source="{StaticResource appbar_folder}" />
<Binding Mode="OneWay"
Source="{StaticResource appbar_folder_open}" />
<Binding Mode="OneWay"
Source="{StaticResource appbar_page}" />
</MultiBinding>
</VisualBrush.Visual>
</VisualBrush>
</Rectangle.OpacityMask>
</Rectangle>
<TextBlock Grid.Column="1" Margin="3" VerticalAlignment="Center"
Text="{Binding Path=FileName}" />
</Grid>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
And the XAML designer in VS2015 is crashing width System.Runtime.Remoting.RemotingException. However if I remove ItemsPresenter from the ControlTemplate, then the XAML designer starts working again.
Either way it compiles and runs, although without the ItemsPresenter I don't get the expected tree like result.
Am i doing something wrong? why does the XAML designer crash? Could this come back to bite me if i ignore it?

Answer 1

Ok solved this
Moving the HierarchicalDataTemplate from TreeView.ItemTemplate into TreeView.Resources fixes the problem.
Go figure