Our firm created a workaround to accomplish this feature. We created a new matter titled "[Staff Member's] Stuff" and changed the Matter Permissions to only give that staff member access. LexWorkplace Admins will still always have access to that 'folder' (so a staff member should know there's no true privacy), but no other user can see that 'private' user folder with the permissions set that way. Users would still have to access that folder through the main "matters" tab versus a dedicated side bar menu button, but it's definitely effective for each user to have individuals docs stored.