Load two different images, Image A and Image B (into Main and Comp slot)
Go to Copy (Copy Map Items)
Select Copy From Main To Comparison and copy a selected item.
(in my case Temp Conv)
Click on OK, and the item (map) seems to have been copied.
(shows no longer as difference)
Click on the Save Icon of the Comparison Image (overwrites file B)
When you now try to close NT a requester comes up ' Image B not saved'
Click NO -> Exit
Now restart NT and Load A and B files (if not loaded already).
Both files are now identical!
Magic!
![Smile :)](./images/smilies/icon_smile.gif)