Highlighting returns entire field in Ferret trunk?

Hello,

I’m using Ferret trunk (#770) with Kyle’s large file support patch:
http://ferret.davebalmain.com/trac/ticket/215

I’m having trouble with Ferret::Search::Searcher#highlight returning too
much text around the query term. Regardless of what I set
:excerpt_length to, highlight returns the entire contents of the field
up to the first occurrence of the search term.

Any suggestions?

-Stuart