title: trying to call selectize with different parameter, but it runs with old value
body: <p>I have a function which receives a parameter and then calls [selectize.js][1]. </p>
  
  <p>Initially I call <code>myFunc</code> with <code>param</code> equal 1. It works, the data comes from server, and I get a dropdown list with it. </p>
  
  <p>But later I call <code>myFunc</code> with another <code>param</code> value, let's say 2. </p>
  
  <p>And I see in the console, that <code>myFunc</code> receives 2, but <code>load</code> function and ajax <code>success</code> function log 1 to console, and data comes as if <code>param</code> value was 1. </p>
  
  <p>If I call <code>myFunc</code> with <code>param</code> equals 2 first time, the data comes as if <code>param</code> value is 2. </p>
  
  <p>I tried to add to both <code>load</code> and ajax <code>success</code> function <code>cache: false</code>. But <code>load</code> function continues to use old <code>param</code> value.</p>
  
  <pre><code>function myFunc(param) {
      console.log(param);
      $("#select-control").selectize({
          valueField: 'id',
          labelField: 'name',
          searchField: 'name',
          options: [],
          create: false,
          render: {
              option: function(item, escape) {
                  return '&lt;div&gt;' + escape(item.name) + '&lt;/div&gt;';
              }
          },
          score: function(search) {
              return function(item) {
                  return 1;
              }
          },
          load: function (query, callback) {
              console.log("selectize loading data");
              console.log(param);
              this.clearOptions();
              $.ajax({
                  url: "/api/some/end/point",
                  type: 'GET',
                  data: {
                      q: query,
                      some_param: param
                  },
                  error: function () {
                      callback();
                  },
                  success: function (res) {
                      console.log(res);
                      console.log(param);
                      callback(JSON.parse(res));
                  },
              });
          }
      });
  }
  </code></pre>
  
  <p>Here is edited log from the console</p>
  
  <pre><code>23378 // myFunc received this value as param
  selectize loading data // load function is called
  23378 // param value inside load function
  {/* here is the response, which contains data */}
  23378 // param value inside ajax success function
  19476 // myFunc received new value
  selectize loading data // load function is called
  23378 // but the load function uses the first param value, it should be 19476 here
  {/* the same old response, param didn't change*/}
  23378 // and ajax success function also uses the old value, it also should be 19476
  </code></pre>