Review the differences between an attached xref and the referenced drawing file.
The Xref Compare visor opens and the comparison results display in the current drawing. This visor provides several commands and settings to review and control the comparison result.

Differences between the comparison drawing and the attached xref are grouped by proximity into change sets that are surrounded by revision clouds. Differences are separated by color. By default, the colors are assigned as follows:
Click to reverse the draw order between overlapping objects in the xref and the referenced drawing file in the comparison. By default, the objects in the host drawing are displayed above the objects in the referenced drawing file.
Revision clouds are used to highlight the differences between an attached xref and the referenced drawing file.
The size of the change sets is determined by the proximity of the changed objects compared to the size of the revision clouds.
Click to hide hatch object comparisons in your comparison result
Click to hide text object comparisons in your comparison result
Click to hide the comparison results temporarily as you work in the current drawing.
Click the right and left arrows to zoom in to the next or previous change set.
Click to end the comparison and close the DWG Compare visor.