Isolating Changed Dimensions
To isolate all changed dimensions:
Click Isolate Changed Dimensions 
(Dimensions/Relations toolbar) or .
The changed dimensions highlight, all other dimensions turn gray, and the cursor changes to 
. If you hover over a changed dimension, the tooltip shows the previous dimension.
You can use Isolate Changed Dimensions even if the Use specified color for changed drawing dimensions on open option is cleared. Isolate Changed Dimensions allows you to view changed dimensions on demand rather than automatically when you open the drawing, giving you the flexibility to see the changed dimensions only when you want to see them.