Template Family restriction (no or one) can be overuled by editing an existing page

[KarlvonKarton]

When I set the family of a template not to be used for a new page, then I can not add/create a new page with that template.  All good.

But when I edit the template of an existing page, then I can select and save that ('disabled') template... 

So I can still have more than one page with a ('disabled') template that only can have one or not at all ... 

How is that possible?

[Robin S]

I guess it depends on the needs of your site, but I've never needed to give the "page-template" permission that allows a role to change the template of a page to any role other than superuser. And as a general rule in PW the superuser role can do anything and isn't affected by restrictions.

[teppo]

18 hours ago, KarlvonKarton said:

When I set the family of a template not to be used for a new page, then I can not add/create a new page with that template.  All good.

But when I edit the template of an existing page, then I can select and save that ('disabled') template... 

So I can still have more than one page with a ('disabled') template that only can have one or not at all ... 

How is that possible?

This is by design. See this GitHub issue for more details. It's not the most consistent solution, but admittedly I've found it quite useful too.