If you find that your jquery autocomplete plug-in specifically the fcbkcomplete variant works nicely when you load the entire document, but doesn't work when you make requests through ajax to display the content in a dv tag, you might want to try this.

Basically if it's inited in a page that was requested through ajax with content passed into a div tag. It doesn't display the autocomplete suggestions. I found this but to be caused by width being set to "0px" in the messagetofeed <li> attribute.

My workaround for this was to add
feed.css("width", "512px"); // set to default width

on lines 407, and 416 in jquery.fcbkcomplete.js.

I have commented on this on the developers site hope he picks it up.