Autocomplete in a cell of a table

I'm having trouble adapting this autocomplete example to my table. I want to put autocomplete in the designation cell. What happens is this:

HTML TABLE

<table class="table table-striped table-bordered" id="vendaTabela" width="100%" >
 <thead>
   <tr>
     <th data-class="expand">Cód.</th>
     <th data-hide="phone">Designação</th>
     <th data-hide="phone">Qnt.</th>
     <th data-hide="phone,tablet">Uni.</th>
     <th>Preço</th>
     <th>Desconto</th>
     <th>IVA</th>
     <th>Sub-Total</th>
     <th></th>
   </tr>
 </thead>
 <tbody>
   <tr id="tr0">
     <td class="codigo" contenteditable="true" onblur="codArtigo ( )"></td>
     <td id="tags" class="designacao" contenteditable="true" onblur="nomeArtigo()"></td>
     <td class="quantidade" contenteditable="true" onblur="subtotal ( )"></td>
     <td class="unidade" contenteditable="false"></td>
     <td class="preco" contenteditable="true"></td>
     <td class="desconto" contenteditable="true"></td>
     <td class="iva" contenteditable="false"></td>
     <td class="total" contenteditable="false"></td>
    </tr>
  </tbody>
</table>

JAVASCRIPT

var availableTags = [
            "ActionScript",
            "AppleScript",
            "Asp",
            "BASIC"

        ];
$( "#tags" ).autocomplete({
   source: availableTags
        });

So far so good the issue is that by putting the 'id="tags"' in the 'td' of the designation, spoils me the layout of the table:

Itmakesmethereakindofcolapsanofthedesignationwithquantity.Doesanyoneknowwhatthatmightbe?

EDIT

Wheninspectingelement,itisaddingone:

Is there a way to "escape" this?