title: Dropzone opens file chooser twice
body: <p>I have set up dropzone with a clickable element. Clicking the button causes dropzone to open the file chooser twice, instead of just once, the second coming immediately after the first file has been chosen.</p>
  
  <p>The init code is:</p>
  
  <pre><code>Dropzone.autoDiscover = false;
  
  $(document).ready(function(){
  
  // Remove the template from the document.
  var previewNode = document.querySelector("#template");
  previewNode.id = "";
  var previewTemplate = previewNode.parentNode.innerHTML;
  previewNode.parentNode.removeChild(previewNode);
  
  $("div#photo").dropzone({
      url: "/blackhole/",
      thumbnailWidth: 240,
      thumbnailHeight: 240,
      parallelUploads: 1,
      maxFiles:1,
      maxFilesize: 5,
      uploadMultiple: false,
      previewTemplate: previewTemplate,
      autoProcessQueue: true,
      previewsContainer: "#photoPreview", 
      clickable: ".fileinput-button",
      init: function() {
          this.on("maxfilesexceeded", function(file) {
              this.removeAllFiles();
              this.addFile(file);
          });
      }   
  });
  </code></pre>
  
  <p>And the page elements are:</p>
  
  <pre><code>      &lt;div class="table table-striped" class="files"&gt;
  
          &lt;div id="photo"&gt;
            &lt;div id="actions" class="row"&gt;
              &lt;div class="col-lg-7"&gt;
                &lt;button type="button" class="btn btn-success fileinput-button"&gt;
                  &lt;i class="glyphicon glyphicon-plus"&gt;&lt;/i&gt;
                  &lt;span&gt;Choose file...&lt;/span&gt;
                &lt;/button&gt;
              &lt;/div&gt;
            &lt;/div&gt;
          &lt;/div&gt;
  
          &lt;div class="files dropzone-previews" id="photoPreview"&gt;
            &lt;div id="template" class="file-row"&gt;
              &lt;div&gt;
                &lt;span class="preview"&gt;&lt;img data-dz-thumbnail /&gt;&lt;/span&gt;
              &lt;/div&gt;
              &lt;div&gt;
                &lt;p class="name" data-dz-name&gt;&lt;/p&gt;
                &lt;strong class="error text-danger" data-dz-errormessage&gt;&lt;/strong&gt;
              &lt;/div&gt;
              &lt;div&gt;
                &lt;p class="size" data-dz-size&gt;&lt;/p&gt;
                &lt;div class="progress progress-striped active" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0"&gt;
                  &lt;div class="progress-bar progress-bar-success" style="width:0%;" data-dz-uploadprogress&gt;&lt;/div&gt;
                &lt;/div&gt;
              &lt;/div&gt;
              &lt;div&gt;
                &lt;button data-dz-remove type="button" class="btn btn-warning cancel"&gt;
                  &lt;i class="glyphicon glyphicon-ban-circle"&gt;&lt;/i&gt;
                  &lt;span&gt;Cancel&lt;/span&gt;
                &lt;/button&gt;
              &lt;/div&gt;
            &lt;/div&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>Strangely, even though I have added code to replace the any existing file with a later one (so only one file can be uploaded), the second file chooser dialog lets me add a second file.</p>
  
  <p>Its like dropzone has been initialized twice, but I checked that it is only initialized once, and also added the autoDiscover = false option for good measure.</p>
  
  <p>Can anyone spot my mistake?</p>