diff --git a/common/lib/xmodule/xmodule/js/src/collapsible.coffee b/common/lib/xmodule/xmodule/js/src/collapsible.coffee
index 2f4b84e253..18a186e106 100644
--- a/common/lib/xmodule/xmodule/js/src/collapsible.coffee
+++ b/common/lib/xmodule/xmodule/js/src/collapsible.coffee
@@ -16,6 +16,7 @@ class @Collapsible
     el.find('.collapsible header a').click @toggleHint
 
   @toggleFull: (event) =>
+    event.preventDefault()
     $(event.target).parent().siblings().slideToggle()
     $(event.target).parent().parent().toggleClass('open')
     if $(event.target).text() == 'See full output'