How to Set “Replies” and “Forwards” to always open in Full Screen (Outlook 2013)
By default, if you are reading an e-mail in your Inbox (or other folder), and you hit “Reply” or “Forward”, it will display in the “Reading Pane” instead of a new window. You have to click “Pop Out” to open in a new window. This can be changed so the “Replies” and “Forwards” open in their own window.