Compare Reference with Active

You can set separate display colors for the Reference and the Active content: a custom color for each, or else retain the original colors.
Note: Even if you’ve set separate colors, the background fills of one view may obscure the underlying elements in the other view.
Note the Make Fills and Zones Transparent toggle at the bottom of the Trace & Reference Palette: activate this to make fills and zones transparent in both the Reference and Active views. This way you will “uncover” information that otherwise might have been covered up by a fill in the top view.
Note: This method works best if the Active is shown in its original colors, and the Reference in a different color.
Click the Temporarily Displace Reference button in the Trace & Reference Palette.