diff --git a/unpacked/extensions/MathEvents.js b/unpacked/extensions/MathEvents.js
index ff3c6ae98..fb67e60db 100644
--- a/unpacked/extensions/MathEvents.js
+++ b/unpacked/extensions/MathEvents.js
@@ -114,10 +114,9 @@
     False: function (event) {
       if (!event) {event = window.event}
       if (event) {
-        if (event.preventDefault) {event.preventDefault()}
+        if (event.preventDefault) {event.preventDefault()} else {event.returnValue = false}
         if (event.stopPropagation) {event.stopPropagation()}
         event.cancelBubble = true;
-        event.returnValue = false;
       }
       return false;
     },