title: Document/view architecture
body: <p>I want to implement an application based on the Netbeans Platform which handles data (gathered in a document) and displays them in different ways (in views).</p>
  
  <p>So far, I have created a module with a file type (named Document) and a window. In the window, I have put a JPanel and customized the code to replace the standard JPanel class with the "DocumentVisualElement" class. But instantiating a "DocumentVisualElement" needs a Lookup instance. I have tried to get one with "Lookup.getDefault()" but this triggers an error in the "DocumentVisualElement" constructor : the "DocumentDataObject" can't be found in the Lookup.</p>
  
  <p>Have I missed something? Is there a better way to do what I want to do?</p>
  
  <p>Thanks in advance for the time you will spend trying to help me.</p>