299603 2025-09-26 06:52:27 -0700 elements created via parsing can customize with a null registry 2025-10-27 20:17:56 -0700 1 1 1 Unclassified WebKit DOM Safari 26 Unspecified Unspecified NEW InRadar P2 Normal --- 154907 1 steveorvell webkit-unassigned ahmad.saleem792 annevk rniwa webkit-bug-importer oldest_to_newest 2146152 0 steveorvell 2025-09-26 06:52:27 -0700 When setting `innerHTML` or using `insertAdjacentHTML` on an element or shadowRoot with a customElementRegistry set to null, any custom element candidates in the parsed HTML should not customize based on step 7 of "parsing HTML fragments" (https://html.spec.whatwg.org/#parsing-html-fragments). However, they can customize in some cases which results in a customized custom element with a null customElementRegistry. See reproduction: https://codepen.io/Steve-Orvell/pen/RNrroxV?editors=1000 2148131 1 webkit-bug-importer 2025-10-03 06:53:19 -0700 <rdar://problem/161893045> 2148132 2 webkit-bug-importer 2025-10-03 06:53:22 -0700 <rdar://problem/161893031> 2154628 3 ahmad.saleem792 2025-10-27 20:17:56 -0700 Syncing tests here - https://github.com/WebKit/WebKit/pull/53067 added by Blink - https://chromium-review.googlesource.com/c/chromium/src/+/7023674