Create Model Navigator

1. Create new view with a normal TreeViewer? (for example)
2. Use AdapterFactoryContentProvider as content provider and AdapterFactoryLabelProvider as label provider. It should be something like that:
   

   AdapterFactory adapterFactory = ExhibitionDiagramEditorPlugin
           .getInstance().getItemProvidersAdapterFactory();
   viewer.setContentProvider(new AdapterFactoryContentProvider(adapterFactory));
   viewer.setLabelProvider(new AdapterFactoryLabelProvider(adapterFactory));
   

3. Set the input of the viewer like that: (Maybe there is a better way, but I didn't found it yet...)
   

   IEditorPart edp = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getActiveEditor();
   viewer.setInput(((DiagramDocumentEditor)edp).getEditingDomain().getResourceSet());
   

4. You can inherit from the content and label provider to customize them for your needs.