How to spot loops from the internal table viewer?

[#1]

I am following a guide where there is an example of a loop. According to the author it is obvious that the line dotted lines helps you identify the problem:

"

"

In this case the address field is the problem. Yes it is clear that they are there twice, but how does these dotted lines help you identify that?

[#2]

Generally in Orcale, We are using '||' to concatenate the Fields or strings

In Qlikview we are using '&' to concatenate the Fields or strings