[css-contain-2] Per WG resolution, hidden elements don't generate boxes in the top layer. w3c#6728

Author: tabatkins

css-contain-2/Overview.bs

@@ -1696,6 +1696,11 @@ Restrictions and Clarifications {#cv-notes}
 	to their "proper" values from the cascade),
 	no transitions are started.
 
+11. While an element is [=skipped=],
+	if it is placed in the [=top layer=],
+	it does not generate any boxes,
+	as if it were ''display: none''.
+
 
 
 Accessibility Implications {#cv-a11y}