1. Inherit startpage and create a new pagetype for the other pages. Disable editing / remove that property. Convert old pages to new pagetype in admin mode.
2. Add validation to startpage and check if someone has edited that property. Show error message...
3. Hide the property in a tab that requires administer access rights. Don't give editors permission for the non-root start pages...
You can also write an editor descriptor and add your rules for when a property is shown (based on OwnerContent parent type), see this post for inspiration:
I am working with EPi 9, and I have the following issue:
The pagetype StartPage is used multiple times, not just for the root node. I have a property that I want to be editable (in edit mode) only in the root node. Not in the subpages.
Is there a way to do this, without enabling the dynamic properties?
Regards, Torunn Surnflødt