title: System.Windows.Interactivity: Could not load file or assembly 'System.Windows, Version=2.0.5.0
body: <p>I am trying to reference System.Windows.Interactivity in order to <a href="https://stackoverflow.com/questions/4731718/does-treeview-use-command-bindings-for-expand-collapse">support IsExpanded behavior command</a></p>
  
  <p>But as soon as i add a reference to this assembly, i get the error loading System.Windows 2.0. This appears to be a known bug, and solution appears to be to just reference that assembly.</p>
  
  <p>I downloaded Silverlight SDK, and referenced assembly in question in my project. </p>
  
  <p>however, now i am getting lots of conflicts between System.Windows, and WindowsBase.dll. Classes such as RoutedEventHandler exist in both.. Must be a way to fix this, since i see people being successful in using that Interactivity dll with wpf 4.0.. </p>