The Highlight Isometric Offsets command is used to identify pipes in the isometric diagram that have been offset using the Offset Isometric or Offset Multiple Isometric command.
To highlight isometric diagram offsets on the drawing, go to
Ribbon: DM Plumbing->Isometrics-> 
Highlight Isometric Offsets
Pulldown Menu: DM Plumbing->Isometrics->Highlight Isometric Offsets
You will be prompted to identify the isometric diagram to be highlighted.
Select isometric:
All of the offset pipes in the isometric diagram will be highlighted. A line will be displayed between the origin of the isometric diagram and each pipe to help you locate the highlighted offset pipes.