diff --git a/rapids/templates/rapids/mark.html b/rapids/templates/rapids/mark.html
index da75779c..5e55a3d1 100644
--- a/rapids/templates/rapids/mark.html
+++ b/rapids/templates/rapids/mark.html
@@ -117,7 +117,7 @@
         <div class="offcanvas-header">
         </div>
         <div class="offcanvas-body">
-        <div id="single-dicom-viewer" data-images="{{question.get_image_url_array}}"
+        <div id="single-dicom-viewer" class="dicom-viewer" data-images="{{question.get_image_url_array}}"
             data-annotations='{{question.get_image_annotations}}'>
         </div>
         </div>