In Office 2013 you can reply "in-line". Meaning, you don't have to open a new window with the email.
If you chose drafting the email in a new windows then you have the option in the tab "Options". And you can also add it to the QAT (Quick access toolbar). That's ok!
However, if you are replying in-line the new tab "Compose tools/Message" will open, and there you will have to go to "Tags" and activate it from there whenever you want. I created a new group in that "Compose tools/Message" but the option "Request read receipt" is not available in "All commands".
Do you know any workarounds? Thanks!