I’m sure it used to be possible to make a post be a dismissible “banner” post which would appear at the top of every page. I can see that now there’s an option for a welcome banner with a search bar. Did that replace the banner post?
Weirdly when I pin and unpin a topic, the menu option remains “Un-pin topic” (though the correct modal does pop up).
Also on the “Feature this topic” the third section beginning “There is no banner topic” does not appear.