when reply or forward to a request the mail conversation is not shown in-line

when reply or forward to a request the mail conversation is not shown in-line

I have one user where when he replies or forwards a request the original request and subsequent replies are not added to the mail as in-line text.

for all the other users this problem does not exist. i was therefore wondering if it is a user option and if so where to find the option because i cant find anything about this.