[whatwg/dom] window.event and shadow trees (#679)

In https://chromium-review.googlesource.com/c/chromium/src/+/1177406 Yuki Yamada corrected a wpt test that now illustrates that if a listener of a node in a shadow tree runs for a composed event, `window.event` will be undefined.

If this listener were to call a function that's not aware of the shadow tree, but does keep around state about the composed event, it'll learn about the existence of the shadow tree.

I think this is only observable with web developer-implemented shadow trees, not UA-implemented shadow trees, but it still seems somewhat suboptimal? Am I missing something here?

cc @whatwg/components 

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/whatwg/dom/issues/679