A bit of terminology.
1. Editable outlines.
2. Watched outlines.
Editable outlines live in the Fargo sub-folder of your Dropbox Apps folder. Open them with the File/Open command.
Watched outlines live elsewhere. You can open them in read-only mode via the Open By URL command, also in the File menu. When they update, your view of them updates. Until now you had to keep the URLs of these outlines somewhere else, or leave the tabs open all the time.
The Bookmarks menu is for watched outlines.
It behaves more or less like the Bookmarks menu in a web browser. When you have opened an outline that you want to remember, choose Add Bookmark from the Bookmarks menu. A dialog appears asking what you want to call the bookmark. We suggest the title of the outline (or the long title if it has one).
When you choose Edit Bookmarks, a new tab opens with the contents of the menu in an outline. You can edit the bookmarks there. The menu contains link nodes. You can change the text, or the URLs associated with the items, and reorganize the menu in any way you like.
Only the top level headlines are included in the Bookmarks menu.