TYPO3 Core

i can't reproduce this.
in css_styled_content it works.
in fludi_styled_content i can't choose the header_position

I've used fluid_styled_content only. Inlcuding the optional css styles.
But however, when I try to reconstruct the issue, I am failing.

In Backend the header_position field is not visible anymore:

This solves the issue. No clue why I've seen the field before.

Then, I close this for now, thank you

If you think that this is the wrong decision or experience this issue again, then please write to the mailing list typo3.teams.bugs with issue number and an explanation or open a new ticket and add a relation to this ticket number.