Close Button on Proof Viewer

I would double check yoru environment because the x button still appears in the right top part of the proofing viewer for me

I submitted a ticket as it's not there with us in any of our environments and had it confirmed by Adobe that it is a feature that is no longer supported. I was directed to submit a feature request and they would perhaps look at adding it back in the future. 

We had the same issue and I got the same feedback from support. I was going to submit the same Idea.

For those who are currently using the New Home experience, Workfront did recently deploy a fix mid September to allow for Proofs to open in a new browser tab. This will be the new expected behavior versus having the X close button in the upper right corner of the proofing window.