Bugzilla – Bug 20604
[Shadow]: Event's relatedTarget must be pre-computed before event dispatch
Last modified: 2014-05-29 08:03:17 UTC
"The MouseEvent relatedTarget attribute must return the adjusted related target"
We need to compute related target ahead of time, since DOM operations in event listeners could affect the DOM structure.
*** Bug 20615 has been marked as a duplicate of this bug. ***
Made it clear at https://github.com/w3c/webcomponents/commit/fc19892ff6bf099323447f6a29808630ca66c348
Let me close.