autocomplete does not search when a map is assigned to it

when you start typing in a autocomplete textbox, if you assign a prefetched map to it, then it won't search through the list and will show the entire list instead.

by clicking on http://jsfiddle.net/6kMz2/ you will see 3 textboxes. first one is the ordinary list, so for example if you type "j" all values that has "j" in it will appear.

I assigned a map to second autocomplete textbox instead of a simple list. So if you type "j" you will see all list will show up.

Third textbox is the enhancement I made to be able to shorten the displaying values based on the user input.

I think current functionality of autocomplete is limited and it need enhancement.