title: Does the WinForms Control.Invoke rule apply to contained objects?
body: <p>I understand that multi-threaded WinForms apps are required to use <code>Control.Invoke</code> or <code>Control.BeginInvoke</code> when accessing a control from a thread other than the UI thread.</p>
  
  <p>But does this rule also apply when manipulating objects that are contained within a control but which do not derive from the <code>Control</code> base class?</p>
  
  <p>For example, when using a <code>WebBrowser</code> control, is it OK to manipulate the DOM without using <code>Control.Invoke</code>?</p>
  
  <p>Thanks,
  Tim</p>