Displays Smart P&ID display categories. Categories that are currently displayed are highlighted on this dialog. Selecting a category toggles its setting. P&ID controls display and symbology through the use of drawing filters. The P&ID graphics in the converted IGDS format are not organized into familiar categories such as piping, equipment, or instruments, instead the software displays MicroStation levels 1 through 63 as Smart P&ID drawing filters. Some of the categories are turned off automatically to hide blank label enclosures and inactive heat tracing graphics.