title: Eclipse set action visible on custom complex conditions
body: <p>I want to restrict, set visible false, some actions in an eclipse rcp application, based on user role.</p>
  
  <p>For example when opening editor A, if the user has admin role, show actions 1-2-3-4, but if the user doesn't have admin role, show only actions 1-2.</p>
  
  <p>The action <code>enablesFor</code> property is too simple for my need.</p>
  
  <p>Is there a way to do this in an eclipse rcp application ?</p>