When combining a number of slides to create a new presentation, if the slide numbers are originally set to 1 then auto numbering seems to work and the slides numbers are correct in the generated presentation.
If the slides already contain a slide number greater than 1 then the slide seems to keep its original numbering instead of inheriting from the presentation.
Any advice on this is it a bug? I also have problem with HeaderFooter.IsPageNumberVisible when I set this to false the page numbers still show. I have attached a ‘problem’ slide and one that is ok (this was previously cloned using Aspose and was renumbered as 1 during the cloning operation)
This is a correct behavior, because even if you delete slides in MS-PowerPoint which are numbered, MS-PowerPoint will renumber them. Setting it false is making them disappear.
I found in your problem.ppt, it is not auto page number; it is actually a textframe that contains the manually added number 13. If you open it in MS-PowerPoint and then see the HeaderFooters -- > Slide number check box, you will see it is unchecked.