The point of it
It is fairly common for a concordance to show you repeated wordings: you may wonder whether your corpus contains unwanted repetition.
How to do it
With a concordance on screen, choose Edit | Remove duplicates in the menu. If there are duplicates, you will find the last one marked for deletion. You can prowl up and down the duplicates so found using the < and > buttons.
A duplicate here means concordance lines where all the words and punctuation from 5L to 5R are identical. Outside those horizons no check is made, so these are near duplicates.
The procedure seeks out , and then marks one copy for deletion.
The line above is only in the first 11% of the text; the one below is more than half way through the text.
See also: duplicate corpus contents.