I am trying to load data for jQuery plugin Selectize.js via ajax, but I am not able to delete options loaded with previous calls from dropdown element.

I am stuck with this code where I am able to load data via ajax and show them in dropdown, but I would like to delete them when dropdown is closed (because also typed text is deleted) and load a new ones from another ajax call (after new text is typed), but commands clearOptions(true) / refreshItems() does not delete anything. I would like to delete only items in dropdown. If any item is selected, it should stay so.

var selectize = $('#selectize').selectize({
    sortField: 'text',
    loadThrottle: 500,
    load: function(query, callback) {
      if (query.length < 2) return;

      selectize[0].selectize.clearOptions(true); // this line does not do anything with options in dropdown menu. Even in combine with the line below.
      selectize[0].selectize.refreshItems();

      // simulation of ajax load
      var ajax_data = [{'value': '31', 'text': 'aaa yyy'}, {'value': '32', 'text': 'aaa xxx'}, {'value': '33', 'text': 'bbb xxx'}];
      callback(ajax_data);

      selectize[0].selectize.open();
    }
  });