Bookmark
Bookmarks are links to Rung that make it easy to get back to Rung you saved.
To save Bookmark, click the Rung that you want to save and click Tool -> Bookmark and choose
Save/Delete Bookmark.
The Bookmark appears next to Rung number.
If you delete a Bookmark, click Tool -> Bookmark and choose Save/Delete Bookmark.
You can also move previous bookmark or next bookmark with icon.