255640 2023-04-18 21:06:18 -0700 Declarative shadow DOM does not block rendering on <link> (browser inconsistency) 2023-05-01 18:37:24 -0700 1 1 1 Unclassified WebKit DOM WebKit Nightly Build Unspecified Unspecified NEW BrowserCompat, InRadar P2 Normal --- 148695 1 mic.gallego webkit-unassigned annevk karlcow rniwa webkit-bug-importer oldest_to_newest 1949651 0 mic.gallego 2023-04-18 21:06:18 -0700 Hi, While trying the declarative shadow DOM, I found that Safari does not block rendering if it encounters a <link> external stylesheet, causing FOUC. Chrome, on the other hand, seems to block the rendering until the stylesheet is loaded. I could not find on the spec which behavior is expected, but having inconsistent behavior makes it hard to properly implement a workaround. From a developer point of view, blocking is more desirable (the only way to avoid blocking is to load the stylesheet in the head in the global scope, which leak all the styles). I've raised this concern as well in the W3C repo: https://github.com/whatwg/dom/issues/1187 Thanks. 1951243 1 webkit-bug-importer 2023-04-25 21:07:20 -0700 <rdar://problem/108539923> 1952279 2 karlcow 2023-05-01 18:36:51 -0700 Discussion is started on https://github.com/whatwg/dom/issues/1187 Anne mentioned > Looking at https://html.spec.whatwg.org/#contributes-a-script-blocking-style-sheet and #5465 this would constitute a bug in Chromium, though it does seem somewhat logical to update the