How can I find out what linestyles are contained with a dgn file

Background

When a linestyle is used it is written into the file, however if a user then deletes all the elements containing the linestyle the linestyle definition still remains in the file unless it is removed using File > Tools > Compress Options.

Steps to Accomplish

1. To review all the linestyles using in the file open the Explorer dialog.
2. On the Explorer dialog expand the ' File ' section
3. Scroll down the ' File ' section and expand the ' Line Styles ' by selecting the arrow

This will expose the linestyles that are in the file even if they have been removed as demonstrated in the following video.