Compare Options will open in a focused state, interface will be blurred out while dialog is open:

KCompare Revision Options

Distance Tolerance:
Sets the tolerance threshold for running the Compare session. Typically set to the
minimum acceptable compare value for the files units. Any measures below this threshold
would then pass the compare. By default set to 0.001 (the best expected results from
an IGES file).

NOTE: Tolerance adjustment may need to be performed when the tolerance value is to extreme (having a 0.001 value for a mm file for example).
 
Annotations:
Will include any text or dimension information in the compare.