Hope this is easy to answer without going into the code.
This is related to a custom application, I implemented a Widget Context Provider, and it works as expected for Admins.
For owners, they cannot see the custom widgets or change the custom widgets on application or content pages. They can add widgets to the application or content pages.
Looks like permissions for the widgets with context provider all deny access to anyone not an admin.
(built in applications like blogs are fine, so owners can edit blog context widgets)
I didn't implement any permissions for page content specifically. I did create permissions for basic CRUD on Application and Content.
All of this seems to work fine.