Please add an option for including attachments when replying. That option is available when forwarding, but often the attachments need to be maintained for documentation when replying and BCCing oneself.
Attachment to Reply" is a peculiar case, but a simple one. Just press "Reply" and on the message screen that opens, select the file you want to attach from "Attach" shown at the top. Replies with attachments take a little longer to send.
Often emailing back and forth the same file/s with changes/suggestions to graphics or documents, the attachments are often opened several times for referencing between emails. Continuously having to find and re-attach the same files over and over again when replying is unproductive and frustrating.
Most other email software I've used has this ability. I have been thinking about trying other email software just because of this issue.