In ClearCase, users (admins really) can define custom element types. However, FishEye only considers the following element types as text files:

• text_file
• xml

The fix would be to get details about (custom) file types by executing:

cleartool lstype -l -kind -eltype -invob <vob>

any types that have a supertype (or supertype of a supertype) that equals text_file or xml should be treated as text files.

A workaround is to use only the built-in types text_file and xml.