Each card below is one island (counter + toggle work). Nested inside is a lake — the framed panel — whose own button does nothing, because its component code is not in any client chunk. The accent button inside the lake is another island: it becomes interactive again on its own.

Toggle removes and re-adds the lake. Watch the SSR at stamp: cache restores the same HTML; SWR paints from cache then revalidates through the signed region endpoint and gets a fresh stamp. Full remount API: docs · Remount.