Once you have imported parents from a source document, a link is set up between the source document and the destination document. When you subsequently load parents from the same source document, the association between overridden items and their parent items on reloaded parent pages is maintained. This association lets you keep parent pages in different documents consistent without putting those documents into a book.

If you want to use this method of keeping parent pages consistent, you should load the parent pages from the source document before overriding any objects on the parent. If your document has overridden items and you have never imported parents from any source, those overridden items become detached the first time you load from a source document and replace parent pages with the same name as the parent parent of the overridden items.

If you subsequently import parents from a different source document, however, and choose Replace Parent Pages, the overridden items may become detached. Any same-named parents from the new source document will be applied to the document page containing overridden items, creating two sets of objects.