This is more a tip than anything else for someone like myself who has next to zero experience with the jQueryUI.
In using the Autocomplete widget I noticed that the first letter entered matched against ANY letter in the associated list of words. I thought this to be unconventional behavior. I think most users would want to see only the words that BEGIN with the letter(s) they typed.
At the very bottom of the jQueryUI API page on Autocomplete is an example for matching only the beginning of terms. See Autocomplete API