We are using test environments that use IP addresses only (they have no associated domain name). Studio view mode relies on iframes to show site content, and tries to make scripted changes to the iframe content.

When an IP is used, the browser perceives the admin session and the iframe content as being from different domains. Because of this, the request fails. The Studio page view does not successfully load and is unusable.

Setting a local hosts entry does resolve this issue, but this is not a practical solution as we have multiple changing IPs for these environments.

Reported also in support ticket #6033.