Yes, everything is working fine, and I can even delete a node in the
diagram by using the Edit->Delete menu item.
The only thing that is not working is the delete key in the diagram editor
page. When I press "delete" after having selected a node in the diagram,
nothing happens.
The delete key is working fine in EMF editor pages (in the "selection
tree" for instance).
I think you can reproduce it by simply running the example given in the
article.
There are also warnings about handler conflicts as the following post is
referencing to: http://dev.eclipse.org/newslists/news.eclipse.modeling.gmf/msg16531.html
but I don't think those conflicts are responsible for disabling the delete
key. Actually, I managed to remove those warnings by simply removing
global handlers in the TopicmapActionBarContributor, and the delete key
problem remains in the diagram page.
Of course, when the diagram editor is not embedded in the multipage
editor, the delete key is working fine.
I'm experiencing this problem when running the article example, but also
with my own integrated editor.