diff --git a/lib/javascript-static.js b/lib/javascript-static.js
index 3b60787881d..c74d5a4a865 100644
--- a/lib/javascript-static.js
+++ b/lib/javascript-static.js
@@ -116,12 +116,12 @@ M.util.CollapsibleRegion = function(Y, id, userpref, strtooltip) {
     }
     if (this.div.hasClass('collapsed')) {
         // Add the correct image and record the YUI node created in the process
-        this.icon = Y.Node.create('<img src="'+M.util.image_url(collapsedimage, 'moodle')+'" alt="" />');
+        this.icon = Y.Node.create('<img src="'+M.util.image_url(collapsedimage, 'moodle')+'" alt="" class="icon" />');
         // Shrink the div as it is collapsed by default
         this.div.setStyle('height', caption.get('offsetHeight')+'px');
     } else {
         // Add the correct image and record the YUI node created in the process
-        this.icon = Y.Node.create('<img src="'+M.util.image_url('t/expanded', 'moodle')+'" alt="" />');
+        this.icon = Y.Node.create('<img src="'+M.util.image_url('t/expanded', 'moodle')+'" alt="" class="icon" />');
     }
     a.append(this.icon);