Problem with scriptaculous autocompleter.local

Question

I'm having a problem with Autocompleter.Local. In my list of strings, I have some choices that are substrings of others. For example, "Office" is a substring of "Office park". If I type "Offic", both choices show up. If I type "Office", only "Office park" shows up as a choice. I have tried messing with partialSearch and fullSearch options in all combinations.
Here are the results:

partial    full       result

 1. false  false   Only "office park" shows up
 2. true   false   Only "office park" shows up
 3. false  true    Only "office park" shows up
 4. true   true    Both choices remain, but the order is switched (office park, office) when I type the last character

Also, I have: minChars: -1 so that the list pops up when you hit the down key if there are no characters frequency: 0.01 choices: 100

I'm using array_or_string_for_javascript to turn my ruby array into a javascript array.

I suspect that I might be able to solve this problem with either callback or updateElement, but I don't know how.

Thanks!