Hi John,

From the product help:

• Last segment: this keeps track of the last segment in the last document you worked on. You can navigate to it by double-clicking on the bookmark in the list, or by using the Go to last segment button on the ribbon.
• Last segment in project: this keeps track of the last segment you worked on in any given project. This is useful if you often work on multiple projects at the same time. You can navigate to the bookmark by double-clicking the corresponding bookmark in the list or by using the Go to last segment in project button on the ribbon; this will take you to the last segment in the current project.
• Last segment in document: this keeps track of the last segment you worked on in every document you ever opened. By default, when opening a document, this last segment will be automatically activated so you can continue where you left off last time.

All three of these bookmarks are automatic.