Will clarify that when enableWhen, hidden, read-only or other properties or extensions that control the visibility / editability of an item are set on a group item or a question item with descendant items, those settings apply to all descendants of the group and are not overridden by declarations of the same property on a descendant item.  I.e. if a group is readOnly=true, then all descendants are automatically readOnly=true, regardless of whether they might themselves declare readOnly=false.  Systems may choose to treat conflicting declarations in descendants as an error.