This is a user level issue when signing in to developer.apple.com in Safari. I posted there as suggested: https://discussions.apple.com/thread/256119053

(sorry to dup; didn't see this button earlier) Thanks @DTS Engineer, unfortunately that way results in no smooth animation - the expansion simply "pops". Also in my actual app, I have other animations I'm trying to trigger (e.g. fade effects depending on the expansion state) that this negates. Is there no way to achieve behavior that is similar to the default? VStack works properly, but then I lose the ability handle move/delete operations easily.

Correction: But it still does not allow the list row to smoothly expand/collapse like the default DisclosureGroupStyle.