i am using jquery-ui 1.11.4 with selectmenu autocomplete

My selectmenu has items with values like 4, 44, 5, 55, 555
pressing the keys(4 or 5) multiple times the autocomplete feature selects only the items with value 4 or 5 but not the others

i found the problem in the ui.menu widget (jquery-ui.js)

1. _keydown: function( event ) {
   
2. ........
   
3.         default:
4.             preventDefault = false;
5.             prev = this.previousFilter || "";
6.             character = String.fromCharCode( event.keyCode );
7.             skip = false;
8. 
   
9.             clearTimeout( this.filterTimer );
   
10. 
    
11.            if ( character === prev ) {
12.                 skip = true;
13.             } else {
14.                 character = prev + character;
15.             }
    

if i comment out the "skip check" it works
the autocomplete feature select items with all values 4, 44, 5, 55 and 555

I don't want to change the jQuery-UI files
What are the opportunities to solve this problem (bug?)