I have some items in the content tree that are currently just being used as data items. However, I want to add a layout and various sublayouts to them and I don't want to have to do it manually. Currently these items don't have any presentation details set.
So, I've added the presentation details to the standard values of the template that these items are using. I thought that the items would start using these sublayouts straight away. I know that if a default value is put in after the template has started to be used and the item already has a value the standard values will not overwrite this value, but since the items don't currently have any presentation details (and I've tried resetting them) I thought this would work.
It's probably worth noting that the reason I'm doing this is for previewing purposes so although these can be published, it doesn't necessarily have to happen.