title: Apply style to all TreeViewItem
body: <p>Hi The problem am having is that I have multiple TreeView control and each TreeView has its own TreeViewItem styles,
  setting it </p>
  
  <blockquote>
    <p>TreeView ItemContainerStyle="{StaticResource Style1}"</p>
  </blockquote>
  
  <p>will only set the root element NOT all the child elements, How to apply a style to all the child elements in a TreeView</p>