I deleted an item off a window but somehow managed to delete the window. I found a post that talks about the Rollback feature under the file manager in designer but the rollback option is not shown. Was it moved in version 8 or is there another way to get my page back?
Outside of recovering the old version of the resource via the filesystem (some OSes maintain ‘shadow’ copies, etc) or integrating an external version control system (see: Deployment Best Practices) there is no rollback built into Ignition 8 yet. In the medium term, we’d like to expand the project update script mechanism to make it easier to control external version control systems. In the long term, tighter integration with a particular VCS may be possible (eg, Git in particular).
For now, though, the short answer is that probably your window cannot be recovered to its previous state. We don’t keep history on changed resources internally anymore.
To add on @PGriffith comment; you might benefit from configuring scheduled gateway backups. Its saved me a couple of times when colleagues delete critical resources in a project.
It’s the entire gateway so what I recommend is it restore it on a VM and export the deleted resources and import into your development or production gateway.