diff --git a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/script.js b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/script.js
index 6a3202467e..aa75ac0261 100755
--- a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/script.js
+++ b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/script.js
@@ -28,16 +28,8 @@ table.onmouseout = function(event) {
   // e.g. from <tr> to another <tr>
   if (!currentElem) return;
 
-  // we're leaving the element – where to? Maybe to a descendant?
-  let relatedTarget = event.relatedTarget;
-
-  while (relatedTarget) {
-    // go up the parent chain and check – if we're still inside currentElem
-    // then that's an internal transition – ignore it
-    if (relatedTarget == currentElem) return;
-
-    relatedTarget = relatedTarget.parentNode;
-  }
+  // if we're still inside currentElem, then that's an internal transition – ignore it
+  if (currentElem.contains(event.relatedTarget)) return;
 
   // we left the <td>. really.
   onLeave(currentElem);