public void doubleClick( DoubleClickEvent event )
{
IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
HierarchicalViewer view = ( HierarchicalViewer ) PlatformUI.getWorkbench().getActiveWorkbenchWindow()
.getActivePage().findView( HierarchicalViewer.ID );
TreeViewer viewer = view.getViewer();
// What we get from the treeViewer is a StructuredSelection
StructuredSelection selection = ( StructuredSelection ) event.getSelection();
// Here's the real object (an AttributeTypeWrapper, ObjectClassWrapper or IntermediateNode)