title: Reset select2 value and show placeholder
body: <p>How do I set the placeholder on value reset by select2. In my example If locations or grade select boxes are clicked and my select2 has a value than the value of select2 should reset and show the default placeholder. This script is resetting the value but won't show the placeholder</p>
  
  <pre><code>$("#locations, #grade ").change(function() {
     $('#e6').select2('data', {
       placeholder: "Studiengang wählen",
       id: null,
       text: ''
     });
  });
  
  $("#e6").select2({
     placeholder: "Studiengang wählen",
     width: 'resolve',
     id: function(e) {
       return e.subject;
     },
     minimumInputLength: 2,
     ajax: {
       url: "index.php?option=com_unis&amp;task=search.locator&amp;tmpl=component&amp;&lt;?php echo JSession::getFormToken() ?&gt;=1",
       dataType: 'json',
       data: function(term, page) {
         return {
           q: term, // search term
           g: $('#grade option:selected').val(),
           o: $('#locations option:selected').val()
         };
       },
       results: function(data, page) {
         return {
           results: data
         };
       }
     },
     formatResult: subjectFormatResult,
     formatSelection: subjectFormatSelection,
     dropdownCssClass: "bigdrop",
     escapeMarkup: function(m) {
       return m;
     }
  });
  </code></pre>