Official response
Mario at GemBox
Hi,
We have added support for updating TOC numeric fields, but also other document's numeric fields (Page, PageRef, NumPages, Section, and SectionPages) as well while paginating the document by specifying PaginatorOptions.UpdateFields member to "true".
Now you can remove the use of IsDirty:
toc.IsDirty = true;
And use the following instead:
document.GetPaginator(new PaginatorOptions() { UpdateFields = true });
See Table of Contents (TOC) demonstration sample:
https://www.gemboxsoftware.com/document/examples/c-sharp-vb-net-create-update-word-toc/207
Regards,
Mario