How to highlight something, if it exists, but show error anyway, if it doesn't exist

I think it is necessary to create two checklist entries.

1st entry:

Source: ^. -ABC
Target: ABC
Search mode: Regular Expressions
PowerSearch: On.

This entry will find all segments that contain ABC in target but is missing in source and highlight ABC in target and the 1st character in source.

2nd entry:

Source: ABC
Target: ABC
Search mode: Simple
PowerSearch: On.

This entry will find all segments that contain ABC in source and target. It will also highlight only ABC in source and target.

Regards,
Oscar.