Support sign-in outside the iframe when voting on an embedded roadmap

Visitors who click +1 on an embedded roadmap are redirected to the company’s sign-in page inside the iframe.

If the company blocks iframe authentication, visitors see an error and cannot continue.

The requested flow lets visitors click +1, sign in outside the iframe, then return to the roadmap and vote.

The customer prefers a new tab to reduce concerns about popup blocking.

A sign-in banner does not resolve the failed flow from +1.