Roles & Permissions
Exactly what you can do with the Snapshot and what is visible in the Snapshot tab depends upon the roles you have been assigned. For general information about Content Engine roles and permissions, see Global Roles and Section Roles.
The Snapshot plug-in recognises three different categories of user:
Site administrator (a user with the Administrator role for a site publication).
Blueprint adminstrator (a user with the Administrator role for a blueprint).
The Snapshot tab's Publications page only contains entries for site publications where you have the Administrator role. You can therefore only change a site publication's active blueprint if you are one of the site's administrator.
The Snapshot tab's Blueprints page only contains entries for blueprints where you have the Administrator role. Therefore you cannot do anything to a blueprint unless you are one of the blueprint's administrators.