HTML::Tree seems to have a problem with HTML::Pr; if I use a new
version of either, the pfile test of "make test" fails (because
as_html is dropping the <foo> tags). It was working with HTML::Pr
3.26 and HTML::Tree 3.13 (I haven't checked intermediate versions).

Platform: Solaris 2.6 on Sun Sparc

Perl 5.8.0

HTML::Tagset 3.03

HTML::Pr 3.31

HTML::Tree 3.17