Something has changed in the way Thunderbird is handling Replies. Replies used to be added to the original email with an arrow indicating that the email had been responded to. Now the reply is added to the mail list as a separate email grossly clogging up the list of emails. Sometimes the "replay arrow" is displayed and sometimes not. I do not want the reply shown as a separate email. Is there some setting that will accomplish this? I have been unable to find anything that looks like it would work.

PS The Bold and Italic for this email did not work.