I have a text frame that appears in two parts that is somehow synced/linked, where text added to the frame in one of the parts also appears in the other part.
How can I duplicate that text frame/the page or otherwise replicate this?
I can attach the “magic linked text frame” if that would be useful! (And apologies if this is directly addressed in the manual!)
I don’t think I understand what you are writing. Have you been creating a new page template based on another page template? If so, you are right, all existing frames in the source are linked with those same frames in the new template, meaning if you modify them in the new template, they will be modified in the source template… To avoid this, you need to delete that frame in the new template (it will not delete it in the source template) and create a new one, which will be unlinked. Honestly I don’t know if that helps, or if you are having another problem
Reading your post again, I am thinking that you might have been using a text frame outside a template (which you really should avoid, because it creates overrides, and overrides are the devil), and want to actually turn this into a template. This feature has been already requested (turning an overridden page into a new template to avoid the hassle of doing it all again in the template editor), but is not implemented yet. My advice : create a new page template for this page and use it on both parts (both layouts) where necessary. That would be the elegant Dorico way.