Sheet PR are not preserved if the displayed document and the context document are different instances of the same document

This happens because the SheetDocumentDisplayer puts the displayed document on the context only if it's different than the current document, but the difference is checked by comparing the document references.

You can reproduce this problem by rendering a wiki macro before displaying a document that has a sheet with programming rights. The wiki macro changes the context document before it is rendered and doesn't restore the exact same instance: it restores the saved version, so a different instance of the same document.