<TreeView x:Name="TreeView" FontSize="{Binding TreeViewTextSize}" Grid.Row="2" Margin="10" ItemsSource="{Binding DisplayedItemsTree}"  Effect="{Binding Content_Effect}" IsEnabled="{Binding Content_IsEnabled}"/>

<HierarchicalDataTemplate DataType="{x:Type local:Item}" ItemsSource="{Binding Items}">
            <StackPanel Orientation="Horizontal">
                <Image Height="{Binding ElementName=TreeView, Path=FontSize}" Margin="3 0 5 0" Source="{Binding PathToImage}"/>
                <TextBlock FontSize="{Binding ElementName=TreeView, Path=FontSize}" Text="{Binding Title}" Margin="0 0 5 0"/>
                <ItemsControl ItemsSource="{Binding Items}"
                        ItemTemplate="{StaticResource tplItemRect}"/>
            </StackPanel>
</HierarchicalDataTemplate>