On 11/12/15, ShortStack for Teams replaced the Permissions feature.
All permissions you set up previously are still in effect, and you may still remove permissions. However, granting new permissions, and adjusting existing permissions is no longer supported.
To remove existing permissions for an asset, access the permissions dialog the way you normally would; by clicking on its padlock icon. You may remove individual permissions or click the Remove All Permissions button to revoke all access.