Storage Format Editor shows loss of css classes after a page upgrade

[David May]

We use custom css classes on our pages for our PDF export. In August 2024 we moved from Confluence server to Confluence cloud and chose to use Storage Format Editor for Confluence FREE by K15t Labs. This solution works great.

However, with the forced updated of our legacy pages, the custom css is lost. We have no workaround.

1. Update page and save update (css is lost)
2. Go to Updated Page > ⋯ > Version History and open the page before the update
3. Go to Versioned Page > ⋯ > View Storage Format and copy content (has css)
4. Go to Updated Page > ⋯ > Apps > Edit Storage Format
   1. paste from #3
   2. Save
5. The Updated page now has the css again
6. Modify the page with any new next and save
7. (!) The save page no longer has the css

It looks like the new editor not only strips existing css from legacy pages on conversion but also restrips any newly added css on every save.

This is a nightmare. Does anyone have any solutions? I'm also reaching out to K15t labs.