When file (ex. PDF) is added to Paper document user can comment that in right column. But when the same file is commenting in Dropbox - that comments are visible only in folder / file preview. Maybe it could be possible to merge that comments. So when someone comment a file in Dropbox Paper I could see that comment in Dropbox app folder or on File preview. When someone comment a file in dropbox folder or preview, that comments are visible on that file which is attached to Dropbox Paper doc.