(The bookmarks feature works with NW 7.31 SP4 and later releases, and NW 7.4 SP2 and later releases)
You can now add bookmark to any ABAP artifact in ABAP Development Tools. To add a bookmark, select the artifact in the project explorer, and choose teh context menu “Add Bookmark” and give a name of your choice. That’s it. This ABAP artifact is bookmarked in the Bookmarks view. You can double click on this artifact at any point in time to open its respective editor.
Also, refer to this interesting post on adding bookmarks in source editors
Fig. Select the ABAP artifact and choose “Add Bookmark”
Fig. You can select any ABAP artifact to bookmark
Fig. Enter a new name of your choice.
Fig. The bookmarked objects are available in the Bookmarks view.
You can also bookmark the fields defined inside artifacts such as ABAP Report.