Created attachment 441061 [details] Recording of bug in Safari 14.1 and Safari 15 There is a regression in Safari 15 and TP 133 when a custom HTML element has :hover rules. For context, I'm developing a custom element `app-switcher` that may or not be included in a custom element `ripe-header`. Standalone example: https://www.ripe.net Included in other component example: https://labs.ripe.net (The element in question is the circle with nine dots inside in the top right part of the screen) In Safari 14.1 and 13.1 the standalone element works as expected. In Safari 15 and still in TP 133 the standalone element doesn't change in response to :hover state changes. When the element is included in another custom element (second link), it still works as before. I've added two recordings as an attachment.
<rdar://problem/84214062>
*** This bug has been marked as a duplicate of bug 227422 ***