Whilst implementing Highlight Search Terms (HLST) plugin for a client's website that also uses Cufon font replacement, I found that whenever the HLST plugin kicked in, the Cufon'd text disappeared.
The symptom was that Cufon fonts flash up but it looks like they then go 'invisible' when the HLST JS kicks in. I guessed that the insertion of the
<span class="hilite"> element breaks Cufon's ability to manipulate the DOM (or something!)?
Tried a quick fix. Whacked
Cufon.refresh(); in just before the end of the jQuery document.ready function - i.e. before the last
})); in both compressed and uncompressed versions of the plugin's JS file.
Hope this helps someone!