mong cooperating tags.

 <p>
 For every instance of TagAdapter encountered while traversing the ancestors, the tag handler returned by
 <tt>TagAdapter.getAdaptee()</tt> - instead of the TagAdpater itself - is compared to <tt>klass</tt>. If the tag
 handler matches, it - and not its TagAdapter - is returned.

 <p>
 The current version of the specification only provides one formal way of indicating the observable type of a tag
 handler: its tag handler implementation class, described in the tag-class subeleme