title: Does jquery UI Autocomplete support restrict typing on invalid values where supporting multiple values?
body: <p>I am taking over a new website and it was using a<a href="http://bassistance.de/jquery-plugins/jquery-plugin-autocomplete/" rel="nofollow noreferrer">n old deprecated version of the jquery autocomplete plugin</a>.  I am trying to recreate the functionality using <a href="http://jqueryui.com/autocomplete" rel="nofollow noreferrer">the latest jquery ui autocomplete</a> and there is one feature that i can't seem to replicate.</p>
  
  <p>I am trying to replicate the "mustMatch" functionality in cases <a href="http://jqueryui.com/autocomplete/#multiple" rel="nofollow noreferrer">where there are multiple values allows</a>.</p>
  
  <p>so basically, if i start typing any test that doesn't show up in any of the search results (even partial string search), it resets the entry for that field  (instead of letting me type garbage that is not in the list of valid choices)</p>
  
  <p>So lets say my list (local) is {"Bird", "Song", "Happy"}</p>
  
  <p>It will let me type </p>
  
  <pre><code> Bird, Son
  </code></pre>
  
  <p>but if i type <strong>z</strong> after that it stays on</p>
  
  <pre><code>    Bird, Son
  </code></pre>
  
  <p>to let me know that is an invalid entry</p>
  
  <p>Is this possible to do either in jquery ui autocomplete?</p>
  
  <p>I see a lot of old posts from google asking similar questions <a href="https://stackoverflow.com/questions/2587378/how-to-implement-mustmatch-and-selectfirst-in-jquery-ui-autocomplete">and answers like this one</a>, but none seems to work with multiple values (and many don't seem to work at all :( )</p>