Is 'overlapping' or 'nested' change tracking allowed/supported/generated?

[Nigel Whitaker <nigel.whitaker@deltaxml.com>]

Hello,

My first message here, so please do let me know if I'm in the wrong
place.  Am I correct in assuming that opendocument-users is
for questions of interpretation/implementation of the standard,
and opendocument-comments could be used to point out any errors
that I may spot, inconsistencies etc?


My question is: can/should change tracking sections 'overlap' (either
completely or partially), or be 'nested' for example:

  <text:p>
    The quick
    <text:change-start text:change-id="23"/>
    brown
    <text:change-start text:change-id="42"/>
    fox
    <text:change-end text:change-id="42"/>
    jumps over
    <text:change-end text:change-id="23"/>
    the lazy dog
  </text:p>

This is the completely overlapping case and I can imagine that it could,
in theory, be created by inserting something ('fox') into some text 
('brown jumps over') that had previously also been inserted.


Another case, allowed by the v1.1 specification (as far as I can tell)
is for partial overlap, although I have a harder time envisaging a
use-case for this one:

  <text:p>
    ...
    <text:change-start text:change-id="78"/>
    ...
    <text:change-start text:change-id="42"/>
    ...
    <text:change-end text:change-id="78"/>
    ...
    <text:change-end text:change-id="42"/>
    ...
  </text:p>


Are these cases allowed by the spec?  Are they produced by
anything (I did some simple tests and I couldn't create
any 'overlap' with NeoOffice 2.2.2 or the current GoogleDocs)?

I'm working on an application to support concurrent-editing/sync
of ODT documents and we would like to support/merge the change
tracking information into the output document.  I'd be interested
to know if anyone else has supported these kinds of overlap
in their ODT reading/writing code?

Thanks,

Nigel

-- 
Nigel Whitaker,  DeltaXML: "Change control for XML, in XML"
nigel.whitaker@deltaxml.com    http://www.deltaxml.com