Display themes use color, fills, and hatches to present data that is not typically visible in a drawing. For example, you can specify that all 2-hour fire-rated walls appear with a red fill. The display theme legend activates the display theme in the drawing and identifies the meaning of the different colors, fills, or hatches used in the theme.
The data for display theme legends is collected from the property set data attached to the objects or object styles. Styles for display themes are specified in the Style Manager under Documentation Objects.