Disable selection in TreeView

Question

I see there are ways to disable selection in a ListView, but I haven't seen anything for a TreeView or Grid.

My form is quite basic and looks like this:

Problem is someone can go click on any one of the labels and suddenly it looks like this:

How can I disable this behaviour?

<TreeView Focusable="False">
    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="Focusable" Value="False"/>
        </Style>
    </TreeView.ItemContainerStyle>
    <TreeViewItem Focusable="False">
        <TreeViewItem.Header>Group Header</TreeViewItem.Header>
        <TreeViewItem.IsExpanded>true</TreeViewItem.IsExpanded>
        <Grid Focusable="False">
            <Grid.RowDefinitions>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <Label Content="Message ID">
                <Grid.Row>0</Grid.Row>
                <Grid.Column>0</Grid.Column>
            </Label>
            <TextBox Text="{Binding Path=GroupHeader.MessageId}" HorizontalAlignment="Stretch">
                <Grid.Column>1</Grid.Column>
                <Grid.Row>0</Grid.Row>
            </TextBox>
            <Label Content="Creation Date">
                <Grid.Row>1</Grid.Row>
                <Grid.Column>0</Grid.Column>
            </Label>
            <DatePicker SelectedDate="{Binding Path=GroupHeader.CreationDateTime}">
                <Grid.Row>1</Grid.Row>
                <Grid.Column>1</Grid.Column>
            </DatePicker>
            <Label Content="Instructing Agent">
                <Grid.Row>2</Grid.Row>
                <Grid.Column>0</Grid.Column>
            </Label>
            <TextBox Text="{Binding Path=GroupHeader.InstructingAgent}">
                <Grid.Row>2</Grid.Row>
                <Grid.Column>1</Grid.Column>
            </TextBox>
            <Label Content="Instructed Agent">
                <Grid.Row>3</Grid.Row>
                <Grid.Column>0</Grid.Column>
            </Label>
            <TextBox Text="{Binding Path=GroupHeader.InstructedAgent}">
                <Grid.Row>3</Grid.Row>
                <Grid.Column>1</Grid.Column>
            </TextBox>
        </Grid>
    </TreeViewItem>
   <TreeViewItem>
        ...
   </TreeViewItem>
</TreeView>

Using the TreeView.ItemContainerStyle just disables it on the actual item header, not the content within it it seems.

Update: I've tried as the comment from Chris W and the answer about setting the control template suggested, using the following:

<Style x:Key="StretchingTreeViewItemStyle1" TargetType="{x:Type local:StretchingTreeViewItem}">
  <Setter Property="Background" Value="Transparent"/>
  <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ItemsControl}}}"/>
  <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ItemsControl}}}"/>
  <Setter Property="Padding" Value="1,0,0,0"/>
  <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
  <Setter Property="FocusVisualStyle">
    <Setter.Value>
      <Style>
        <Setter Property="Control.Template">
          <Setter.Value>
            <ControlTemplate>
              <Rectangle/>
            </ControlTemplate>
          </Setter.Value>
        </Setter>
      </Style>
    </Setter.Value>
  </Setter>
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type local:StretchingTreeViewItem}">
        <Grid>
          <Grid.ColumnDefinitions>
            <ColumnDefinition MinWidth="19" Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="*"/>
          </Grid.ColumnDefinitions>
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
          </Grid.RowDefinitions>
          <ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}">
            <ToggleButton.Style>
              <Style TargetType="{x:Type ToggleButton}">
                <Setter Property="Focusable" Value="False"/>
                <Setter Property="Width" Value="16"/>
                <Setter Property="Height" Value="16"/>
                <Setter Property="Template">
                  <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                      <Border Background="Transparent" Height="16" Padding="5" Width="16">
                        <Path x:Name="ExpandPath" Data="M0,0 L0,6 L6,0 z" Fill="Transparent" Stroke="#FF989898">
                          <Path.RenderTransform>
                            <RotateTransform Angle="135" CenterY="3" CenterX="3"/>
                          </Path.RenderTransform>
                        </Path>
                      </Border>
                      <ControlTemplate.Triggers>
                        <Trigger Property="IsChecked" Value="True">
                          <Setter Property="RenderTransform" TargetName="ExpandPath">
                            <Setter.Value>
                              <RotateTransform Angle="180" CenterY="3" CenterX="3"/>
                            </Setter.Value>
                          </Setter>
                          <Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
                          <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="True">
                          <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF1BBBFA"/>
                          <Setter Property="Fill" TargetName="ExpandPath" Value="Transparent"/>
                        </Trigger>
                        <MultiTrigger>
                          <MultiTrigger.Conditions>
                            <Condition Property="IsMouseOver" Value="True"/>
                            <Condition Property="IsChecked" Value="True"/>
                          </MultiTrigger.Conditions>
                          <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
                          <Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
                        </MultiTrigger>
                      </ControlTemplate.Triggers>
                    </ControlTemplate>
                  </Setter.Value>
                </Setter>
              </Style>
            </ToggleButton.Style>
          </ToggleButton>
          <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="True">
            <ContentPresenter Focusable="False" x:Name="PART_Header" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
          </Border>
          <ItemsPresenter Focusable="False" x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
        </Grid>
        <ControlTemplate.Triggers>
          <Trigger Property="IsExpanded" Value="False">
            <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
          </Trigger>
          <Trigger Property="HasItems" Value="False">
            <Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
          </Trigger>
          <!--<Trigger Property="IsSelected" Value="True">
            <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
          </Trigger>-->
          <!--<MultiTrigger>
            <MultiTrigger.Conditions>
              <Condition Property="IsSelected" Value="True"/>
              <Condition Property="IsSelectionActive" Value="False"/>
            </MultiTrigger.Conditions>
            <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"/>
          </MultiTrigger>-->
          <Trigger Property="IsEnabled" Value="False">
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
          </Trigger>
        </ControlTemplate.Triggers>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
  <Style.Triggers>
    <Trigger Property="VirtualizingPanel.IsVirtualizing" Value="True">
      <Setter Property="ItemsPanel">
        <Setter.Value>
          <ItemsPanelTemplate>
            <VirtualizingStackPanel IsItemsHost="True"/>
          </ItemsPanelTemplate>
        </Setter.Value>
      </Setter>
    </Trigger>
  </Style.Triggers>
</Style>

The result is the text on the TreeViewItem itself is no longer selectable/doesn't get highlighted, but the contents within it still can be.

I've tried setting everything I can think of to Focusable="False" but that doesn't work either, so I am starting to think it isn't related to focus on an item. Especially since if you have nested TreeViews you can have both an inner and an outer item selected at the same time.

Answer 1

As the comment says there are two triggers in the default ControlTemplate of the TreeViewItem that changes the look of an item when its selected.

By removing those triggers you can achieve what you want:

<Window x:Class="TreeViewProblem2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:TreeViewProblem2"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <Style x:Key="TreeViewItemFocusVisual">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Rectangle/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF27C7F7"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="#FFCCEEFB"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF1CC4F7"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF82DFFB"/>
        <PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF818181"/>
        <Style x:Key="ExpandCollapseToggleStyle" TargetType="{x:Type ToggleButton}">
            <Setter Property="Focusable" Value="False"/>
            <Setter Property="Width" Value="16"/>
            <Setter Property="Height" Value="16"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                        <Border Background="Transparent" Height="16" Padding="5,5,5,5" Width="16">
                            <Path x:Name="ExpandPath" Data="{StaticResource TreeArrow}" Fill="{StaticResource TreeViewItem.TreeArrow.Static.Fill}" Stroke="{StaticResource TreeViewItem.TreeArrow.Static.Stroke}">
                                <Path.RenderTransform>
                                    <RotateTransform Angle="135" CenterY="3" CenterX="3"/>
                                </Path.RenderTransform>
                            </Path>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsChecked" Value="True">
                                <Setter Property="RenderTransform" TargetName="ExpandPath">
                                    <Setter.Value>
                                        <RotateTransform Angle="180" CenterY="3" CenterX="3"/>
                                    </Setter.Value>
                                </Setter>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Fill}"/>
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Stroke}"/>
                            </Trigger>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Stroke}"/>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Fill}"/>
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsMouseOver" Value="True"/>
                                    <Condition Property="IsChecked" Value="True"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Stroke}"/>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Fill}"/>
                            </MultiTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
            <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
            <Setter Property="Padding" Value="1,0,0,0"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
            <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TreeViewItem}">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition MinWidth="19" Width="Auto"/>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition Width="*"/>
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"/>
                                <RowDefinition/>
                            </Grid.RowDefinitions>
                            <ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
                            <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                                <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                            </Border>
                            <ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsExpanded" Value="false">
                                <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
                            </Trigger>
                            <Trigger Property="HasItems" Value="false">
                                <Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
                            </Trigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <Trigger Property="VirtualizingPanel.IsVirtualizing" Value="true">
                    <Setter Property="ItemsPanel">
                        <Setter.Value>
                            <ItemsPanelTemplate>
                                <VirtualizingStackPanel/>
                            </ItemsPanelTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>

    <Grid>
        <TreeView Focusable="False">
            <TreeView.ItemContainerStyle>
                <Style TargetType="{x:Type TreeViewItem}">
                    <Setter Property="Focusable" Value="False"/>
                </Style>
            </TreeView.ItemContainerStyle>
            <TreeViewItem Focusable="False">
                <TreeViewItem.Header>Group Header</TreeViewItem.Header>
                <TreeViewItem.IsExpanded>true</TreeViewItem.IsExpanded>
                <Grid Focusable="False">
                    <Grid.RowDefinitions>
                        <RowDefinition></RowDefinition>
                        <RowDefinition></RowDefinition>
                        <RowDefinition></RowDefinition>
                        <RowDefinition></RowDefinition>
                        <RowDefinition></RowDefinition>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto"></ColumnDefinition>
                        <ColumnDefinition Width="Auto"></ColumnDefinition>
                    </Grid.ColumnDefinitions>
                    <Label Content="Message ID">
                        <Grid.Row>0</Grid.Row>
                        <Grid.Column>0</Grid.Column>
                    </Label>
                    <TextBox Text="{Binding Path=GroupHeader.MessageId}" HorizontalAlignment="Stretch">
                        <Grid.Column>1</Grid.Column>
                        <Grid.Row>0</Grid.Row>
                    </TextBox>
                    <Label Content="Creation Date">
                        <Grid.Row>1</Grid.Row>
                        <Grid.Column>0</Grid.Column>
                    </Label>
                    <DatePicker SelectedDate="{Binding Path=GroupHeader.CreationDateTime}">
                        <Grid.Row>1</Grid.Row>
                        <Grid.Column>1</Grid.Column>
                    </DatePicker>
                    <Label Content="Instructing Agent">
                        <Grid.Row>2</Grid.Row>
                        <Grid.Column>0</Grid.Column>
                    </Label>
                    <TextBox Text="{Binding Path=GroupHeader.InstructingAgent}">
                        <Grid.Row>2</Grid.Row>
                        <Grid.Column>1</Grid.Column>
                    </TextBox>
                    <Label Content="Instructed Agent">
                        <Grid.Row>3</Grid.Row>
                        <Grid.Column>0</Grid.Column>
                    </Label>
                    <TextBox Text="{Binding Path=GroupHeader.InstructedAgent}">
                        <Grid.Row>3</Grid.Row>
                        <Grid.Column>1</Grid.Column>
                    </TextBox>
                </Grid>
            </TreeViewItem>
        </TreeView>
    </Grid>
</Window>

This will apply to all TreeViewItems. I'd put these in a ResourceDictionary and then just pull them in from there.

One way to obtain the default ControlTemplate for editing is to use Blend. Here is the option:

Answer 2

As I believe you noticed yourself, the way to disable selection of a particular TreeViewItem is to set it's Focusable property to false. You've achieved partial success utilizing TreeView.ItemContainerStyle - this resulted in disabling selection of the first-level items, but not the nested ones. This is caused by the way a TreeView is designed.

TreeView is basically an ItemsControl which wraps it's items with TreeViewItem containers. The key thing here is that it only contains it's children (first-level items), so the TreeView.ItemContainerStyle is only applied to it's children - hence your results.

TreeViewItem also derives from ItemsControl, and it contains it's own children, so all second-level items are children (and items) of their first-level parents, etc. TreeViewItem also wraps all it's children with TreeViewItem containers - in your case, the Grid inside the TreeViewItem called "Group Header" is wrapped with TreeViewItem, which you can confirm using tools like Snoop. So in order to disable selection of second-level items, you should set TreeViewItem.ItemContainerStyle of all corresponding first-level parent items as you did with your TreeView.

Surely when dealing with multi-level trees it may become problematic to explicitly set TreeViewItem.ItemConainerStyle for all items, so you can utilize implicit style:

<TreeView>
    <TreeView.Resources>
        <Style TargetType="TreeViewItem">
            <Setter Property="Focusable" Value="False" />
        </Style>
    </TreeView.Resources>
    ...
</TreeView>

Now this style will be applied to all TreeViewItem controls (w.r.t. implicit styling rules) within the TreeView - importantly, not only the first-level ones. This should get you the expected results.

Answer 3

I was able to remove the blue highlight while still being able to interact with the underlying controls using this TreeView Style:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:WpfApplication1.resoureces">
    <SolidColorBrush x:Key="GlyphBrush" Color="#444" />
    <Style x:Key="ExpandCollapseToggleStyle" TargetType="ToggleButton">
        <Setter Property="Focusable" Value="False"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ToggleButton">
                    <Grid Width="15" Height="13" Background="Transparent">
                        <Path x:Name="ExpandPath" HorizontalAlignment="Left"  VerticalAlignment="Center"  Margin="1,1,1,1" Fill="{StaticResource GlyphBrush}" Data="M 4 0 L 8 4 L 4 8 Z"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsChecked" Value="True">
                            <Setter Property="Data" TargetName="ExpandPath" Value="M 0 4 L 8 4 L 4 8 Z"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="TreeViewItemFocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Border>
                        <Rectangle Margin="0,0,0,0" StrokeThickness="5" Stroke="Black" StrokeDashArray="1 2" Opacity="0"/>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="{x:Type TreeViewItem}" TargetType="{x:Type TreeViewItem}">
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="HorizontalContentAlignment" Value="{Binding Path=HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
        <Setter Property="VerticalContentAlignment" Value="{Binding Path=VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
        <Setter Property="Padding" Value="1,0,0,0"/>
        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
        <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type TreeViewItem}">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition MinWidth="19" Width="Auto"/>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition Width="*"/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition/>
                        </Grid.RowDefinitions>
                        <ToggleButton x:Name="Expander" Style="{StaticResource ExpandCollapseToggleStyle}" IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"/>
                        <Border Name="Bd" Grid.Column="1" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                            <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
                        </Border>
                        <ItemsPresenter x:Name="ItemsHost" Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsExpanded" Value="false">
                            <Setter TargetName="ItemsHost" Property="Visibility" Value="Collapsed"/>
                        </Trigger>
                        <Trigger Property="HasItems" Value="false">
                            <Setter TargetName="Expander" Property="Visibility" Value="Hidden"/>
                        </Trigger>
                        <MultiTrigger>
                            <MultiTrigger.Conditions>
                                <Condition Property="HasHeader" Value="false"/>
                                <Condition Property="Width" Value="Auto"/>
                            </MultiTrigger.Conditions>
                            <Setter TargetName="PART_Header" Property="MinWidth" Value="75"/>
                        </MultiTrigger>
                        <MultiTrigger>
                            <MultiTrigger.Conditions>
                                <Condition Property="HasHeader" Value="false"/>
                                <Condition Property="Height" Value="Auto"/>
                            </MultiTrigger.Conditions>
                            <Setter TargetName="PART_Header" Property="MinHeight" Value="19"/>
                        </MultiTrigger>
                        <!--<Trigger Property="IsSelected" Value="true">
                            <Setter TargetName="Bd" Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
                        </Trigger>-->
                        <MultiTrigger>
                            <MultiTrigger.Conditions>
                                <Condition Property="IsSelected" Value="true"/>
                                <Condition Property="IsSelectionActive" Value="false"/>
                            </MultiTrigger.Conditions>
                            <Setter TargetName="Bd" Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                        </MultiTrigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

AS you can see the place I made a change is commenting out the following.

                <!--<Trigger Property="IsSelected" Value="true">
                    <Setter TargetName="Bd" Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
                    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
                </Trigger>-->