diff --git a/resources/assets/javascripts/lib/forum.js b/resources/assets/javascripts/lib/forum.js
index 7626d2405a6cfcc007855d8a9828c9b2c0b046ec..e0dd69e15c36a61b86cb91caeccfeef9e20634ae 100644
--- a/resources/assets/javascripts/lib/forum.js
+++ b/resources/assets/javascripts/lib/forum.js
@@ -673,7 +673,7 @@ const Forum = {
                 // jQuery('li[data-id=' + topic_id + '] a.tooltip2').hideAjaxNotification();
 
                 // remove all pasted entries, they are now elsewhere
-                for (id in STUDIP.Forum.clipboard) {
+                for (var id in STUDIP.Forum.clipboard) {
                     jQuery('li[data-id=' + id + ']').remove();
                 }