If you want Déjà Vu to display only the empty segments in the project, e.g. because you want to see if there are any segments left that still need to be translated before exporting, you can do it by using the Segment Selector.
To see all the empty segments in the project, you must make sure that you are currently viewing the whole project in the grid, rather than just an individual file.
Then, click on the segment selector, and select the option Empty Segments.
Now, Déjà Vu will only show you the segments that are still empty.