diff --git a/public/js/icinga/events.js b/public/js/icinga/events.js
index 3616acb5816..563287a2252 100644
--- a/public/js/icinga/events.js
+++ b/public/js/icinga/events.js
@@ -221,7 +221,9 @@
             if (typeof $button === 'undefined') {
                 var $el;
 
-                if (event.originalEvent && event.originalEvent.submitter) {
+                if (typeof event.originalEvent !== 'undefined'
+                    && typeof event.originalEvent.submitter !== 'undefined'
+                    && event.originalEvent.submitter !== null) {
                     $el = $(event.originalEvent.submitter);
                 } else if (typeof event.originalEvent !== 'undefined'
                     && typeof event.originalEvent.explicitOriginalTarget === 'object') { // Firefox