如何左键单击使用DataTemplate创建的TreeViewItems不会选择它们？

<TreeView Name="MyTreeView" VirtualizingPanel.IsVirtualizing="True" VirtualizingPanel.VirtualizationMode="Recycling">
    <TreeView.ItemsPanel>
        <ItemsPanelTemplate>
            <VirtualizingStackPanel IsItemsHost="True"/>
        </ItemsPanelTemplate>
    </TreeView.ItemsPanel>
    <TreeView.Resources>
        <DataTemplate DataType="{x:Type EntityType:MyFixedDevice}">
            <TreeViewItem IsHitTestVisible="True" IsEnabled="True">
            <TreeViewItem.Header>
                <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource NameConverter}}"
                           IsHitTestVisible="True" IsEnabled="True"/>
            </TreeViewItem.Header>
            </TreeViewItem>
        </DataTemplate>
    </TreeView.Resources>
    <TreeView.Items>
        <TreeViewItem Header="Data Warehouse">
            <TreeViewItem.Items>
                <TreeViewItem Header="Platforms">
                   <TreeViewItem.Items>
                       <TreeViewItem ItemsSource="{Binding OBJS, Converter={StaticResource COBJSourceConverter}, ConverterParameter=Fixed}">
                           <TreeViewItem.Header>
                               <TextBlock Text="{Binding RelativeSource={RelativeSource Self},
                                          Path=Parent.Items.Count,
                                          StringFormat=Fixed Devices ({0})}">
                               </TextBlock>
                           </TreeViewItem.Header>
                       </TreeViewItem>
                  </TreeViewItem.Items>
                </TreeViewItem>
            </TreeViewItem.Items>
        </TreeViewItem>
    </TreeView.Items>
</TreeView>
<TreeView Name="MyTreeView" VirtualizingPanel.I