If you receive a long email—or you’re writing one—Outlook lets you split your mail vertically into two panes, so you won’t have to scroll as much to refer to different parts of the email.
If you’ve ever had to deal with a long email full of different people’s replies, you’ll immediately realize how handy this little feature is. You can use the top bar to keep the older part of the conversation in view so that you can refer to it using the bottom bar to type your answer. And of course, that’s just one use. You will surely find many others.
To split an email, click in the reading pane or double-click the email to open it and then press Ctrl+Alt+S. This will place a horizontal divider in the middle of the email, with a separate scrollbar on each panel.