Exactly what is the point of being able to flag paragraph styles as only applying to the template itself and not documents based on the template? Doesn't that sort of undermine the entire point of creating the template in the first place?



And why is it that if I modify a style, changing that control from Only in this document to New Documents based on this template, the change doesn't stick? I go right back into the style and the setting has reverted to Only in this document.

You are misunderstanding the options. "Only this document" creates (or modifies) a style in the current file only. This option is always selected when you (re-)visit the Modify Style dialog box.

"New documents based on this template" adds the style to the attached template (which is often the Normal template unless you specifically created the document based on another template).

The style will be copied to the template exactly once. No link is maintained between a style and the template from which the document was originally created.

To put it a bit differently, "New documents based on this template" is never sticky, which is by design. Each time you want to transfer a modified version of a style, you have to explicitly select "New documents based on this template."

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional