Toggle Bookmark
To add or remove a bookmark, set the cursor at the text line and click the Toggle Bookmark
If the cursor line has no bookmark, a new bookmark is added and the Bookmark List is updated.
If the cursor line has a bookmark, the bookmark is removed and the Bookmark List is updated.
Go to Bookmark
If you click the Go to Next Bookmark
If you click the Go to Previous Bookmark
If you select a bookmark from the Bookmark List, the cursor goes to the bookmark.