The example for fragments on the home page does not work with the latest release.
The constructor of a Fragment requires the MarkupContainer to be passed as an argument. It concerns class Index, lines:
item.add(new Fragment("panel", fragmentId));
Specified lines don't compile. I presume there has been an API change.
Suggested modification (by a total n00b with the framework):
super(id, markupId, Index.this);
item.add(new Fragment("panel", fragmentId, Index.this));