Make deleting whole conversations in the message app more clear

Once I accidentally deleted a whole conversation with another person in the messaging app. On the overview page where one can see all the contacts he/she have communicated with by SMS there's also a preview of the last message for each contact. So I called the context menu by tapping on one preview message believing I would delete that message. But in fact I deleted the whole conversation with that person. I think there should be an extra warning apart from the 5 seconds timer when attempting to delete a whole conversation. Or the delete option should get another name like "Delete whole conversation".