[SOLVED] Single File Restore from the PBS Gui

Are you trying to restore single files from a host/container backup, or from a VM? For host/container backups, you can access this menu by expanding the backup group, then expanding a snapshot, then clicking the directory icon in the "Actions" column. For VM backups (and also container backups) this functionality is accessed through PVE (see seciton 16.6.3 of the admin guide[1]).

[1] https://pve.proxmox.com/pve-docs/pve-admin-guide.html#vzdump_restore