This example illustrates how to disable MouseOver highlight when hovering over items in WPF TreeView (SfTreeView)
By default, SfTreeView does not provide the direct support to disable the MouseOver highlight when hovering over items in the SfTreeView. You can disable the MouseOver highlight by overriding the TreeViewItem Template and change the Background property as Transparent in PART_HoverBorder of TreeViewItem Template in SfTreeView.
<BooleanToVisibilityConverter x:Key="boolToVisibilityConverter"/>
<DataTemplate x:Key="busyIndicatorTemplate">
<syncfusion:SfBusyIndicator x:Name="PART_BusyIndicator"
IsBusy="True"
AnimationType="DotCircle"
ViewboxWidth="{TemplateBinding Width}"
VerticalContentAlignment="Center"
VerticalAlignment="Center">
</syncfusion:SfBusyIndicator>
</DataTemplate>
<Style TargetType="syncfusion:TreeViewItem">
<Setter Property="Background" Value="White"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type syncfusion:TreeViewItem}">
<Grid x:Name="ROOT" Background="{TemplateBinding Background}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="DropStates">
<VisualState x:Name="Normal"/>
<VisualState x:Name="DropAsChild">
<Storyboard>
<ObjectAnimationUsingKeyFrames BeginTime="00:00:00"
Duration="00:00:00"
Storyboard.TargetName="BorderContent"
Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<SolidColorBrush Color="#D2DFF2" />
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames BeginTime="00:00:00"
Duration="00:00:00"
Storyboard.TargetName="BorderContent"
Storyboard.TargetProperty="BorderBrush">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<SolidColorBrush Color="#2B579A"/>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames BeginTime="00:00:00"
Duration="00:00:00"
Storyboard.TargetName="BorderContent"
Storyboard.TargetProperty="BorderThickness">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<Thickness>1</Thickness>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames BeginTime="00:00:00"
Duration="00:00:00"
Storyboard.TargetName="PART_ExpanderView"
Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<SolidColorBrush Color="#D2DFF2" />
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Grid.ColumnDefinitions>
<ColumnDefinition MaxWidth="{TemplateBinding IndentationWidth}"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Border x:Name="BorderContent"
BorderThickness="{TemplateBinding BorderThickness}"
BorderBrush="{TemplateBinding BorderBrush}"/>
<Border x:Name="PART_HoverBorder"
Visibility="Collapsed"
Margin="1"
Background="Transparent"/>
<StackPanel x:Name="PART_IndentContainer"
Panel.ZIndex="0"
Orientation="Horizontal"
Grid.Column="0">
<Rectangle x:Name="PART_IndentLine"
StrokeDashArray="2,2"
HorizontalAlignment="Stretch"
Visibility="Hidden">
</Rectangle>
</StackPanel>
<Grid x:Name="PART_LineGrid"
Grid.Column="1"
Panel.ZIndex="0"
Width="{TemplateBinding ExpanderWidth}"
Visibility="Hidden">
<Rectangle x:Name="PART_HorizontalLine"
StrokeDashArray="2,2"
Margin="10,0,0,0"
Width="10"
VerticalAlignment="Center" />
<Rectangle x:Name="PART_VerticalLine"
StrokeDashArray="2,2"
HorizontalAlignment="Stretch"/>
</Grid>
<ContentControl x:Name="PART_ExpanderView"
Focusable="False"
Width="{TemplateBinding ExpanderWidth}"
Visibility="{Binding HasChildNodes, Converter={StaticResource boolToVisibilityConverter}}"
ContentTemplate="{TemplateBinding ExpanderTemplate}">
</ContentControl>
<syncfusion:TreeNodeView x:Name="PART_ContentView" Grid.Column="2"
Margin="4,0,4,0"
VerticalAlignment="Center"
Focusable="False"
ContentTemplate="{TemplateBinding ItemTemplate}">
</syncfusion:TreeNodeView>
<Border x:Name="PART_DragLine" Grid.ColumnSpan="3" Visibility="Collapsed" BorderBrush="#2B579A" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="FullRowSelect" Value="True">
<Setter Property="Grid.Column" TargetName="BorderContent" Value="0"/>
<Setter Property="Grid.ColumnSpan" TargetName="BorderContent" Value="4"/>
<Setter Property="Grid.Column" TargetName="PART_HoverBorder" Value="0"/>
<Setter Property="Grid.ColumnSpan" TargetName="PART_HoverBorder" Value="4"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="FullRowSelect" Value="False"/>
<Condition Property="ExpanderPosition" Value="Start"/>
</MultiTrigger.Conditions>
<Setter Property="Grid.Column" TargetName="BorderContent" Value="2"/>
<Setter Property="Grid.ColumnSpan" TargetName="BorderContent" Value="1"/>
<Setter Property="Grid.Column" TargetName="PART_HoverBorder" Value="2"/>
<Setter Property="Grid.ColumnSpan" TargetName="PART_HoverBorder" Value="1"/>
</MultiTrigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="FullRowSelect" Value="False"/>
<Condition Property="ExpanderPosition" Value="End"/>
</MultiTrigger.Conditions>
<Setter Property="Grid.Column" TargetName="BorderContent" Value="0"/>
<Setter Property="Grid.ColumnSpan" TargetName="BorderContent" Value="3"/>
<Setter Property="Grid.Column" TargetName="PART_HoverBorder" Value="0"/>
<Setter Property="Grid.ColumnSpan" TargetName="PART_HoverBorder" Value="3"/>
</MultiTrigger>
<Trigger Property="ExpanderPosition" Value="Start">
<Setter Property="Grid.Column" TargetName="PART_ExpanderView" Value="1"/>
</Trigger>
<Trigger Property="ExpanderPosition" Value="End">
<Setter Property="Grid.Column" TargetName="PART_ExpanderView" Value="3"/>
</Trigger>
<Trigger Property="ShowLines" Value="True">
<Setter Property="Visibility" TargetName="PART_LineGrid" Value="Visible"/>
</Trigger>
<DataTrigger Binding="{Binding ShowExpanderAnimation}" Value="True">
<Setter Property="ContentTemplate" TargetName="PART_ExpanderView" Value="{StaticResource busyIndicatorTemplate}"/>
</DataTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Opacity" Value="0.3"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
KB article - How to disable MouseOver highlight when hovering over items in WPF TreeView (SfTreeView)?
Visual Studio 2015 and above versions