title: How to handle context menu commands on items in TreeView
body: <p>I am implementing an explorer-type view: on the left is a TreeView and on the right is a details view / editor view of the item selected on the left.</p>
  
  <p>The TreeView contains different types of 'leaf' objects. I have defined HierarchialDataTemplates to define how the objects are presented and which context menu should be presented. The MenuItems have Commands which are bound to the view-model.</p>
  
  <p>What I am struggling with is where to implement the Command handlers. The straight-forward place would be in the 'leaf' view-models but they don't know anything about the 'explorer' view-model and how to open the details/editor view.</p>
  
  <p>The simplest solution would be to bind the leaf context menu to the explorer view-model as this is where the action is best executed.</p>
  
  <p>How is this normally handled? Are there any 'well-known' patterns?</p>