Sliding fields do not slide when located in the header. It might be possible to put them in a leading grand summary part, but then they will only appear on the first page of a multi-page report so this may not work for you.
Key facts about sliding layout objects:
- It's only visible in preview mode and when you print/save as PDF...
- Sliding fields will shrink but not expand.
- All layout objects below and in the same layout part as the slide/resize field need to also be set to slide up and resize.
- Objects in headers and footers will not slide.
- Portals will shrink/slide to fit the number of rows of records, but fields within the portal row will not shrink/slide.
- Fields will slide up only if Top alignment is specified for it and will slide left only if Left alignment is specified.
- Consistent side borders are difficult to achieve with sliding fields.
- In FMP13, hidden objects (”Hide object when”) will slide/resize.
Thank you very much for your insight. I will give the leading grand summary part a try, and keep the key facts about sliding layout objects in mind.