There's a bug in the RDF/XML parser of the Tabulator Firefox Extension. It 
occurs when there are literals that contain CDATA sections. CDATA sections seem 
to work when the entire literal is wrapped in <[CDATA[ ... ]]>, but not if only 
a part of the literal is wrapped.

There's a test case here:
http://richard.cyganiak.de/2008/03/rdfbugs/cdata.rdf

It contains three rdfs:comment literals. One does not use CDATA, one is 
completely wrapped in CDATA, one is only partially wrapped in CDATA. The 
partially wrapped one is not shown by Tabulator, it seems like it's simply 
ignored.