Clarify expectations of meta-data preservation during editing.
To "4.1. XML Display Directives" add:
Editors MAY use displayblock, displaydata and foreign namespaces to
meta-data which SHOULD be preserved by the processor during Sieve script
translation. Some editors find it inconvenient to preserve this
during an editing session. Editors MAY preserve this data during an editing
session for compatibility with other editors.
First, there is already a requirement that such meta-data MUST be preserved by
translation process. So I don' think that part is necessary. That said,
I think an explicit statement of what editors are supposed to do is a good
idea and I've addedd that part of the above text to the document.