How to forward email from a different account?

After switching to the New Outlook, I find I am unable to forward emails or reply to emails from other email accounts I own.

Next to the Send button there is a drop down From: box and it does show the other email accounts I own. But unlike the old Outlook which lets you stay in that email even as you switch to another email account, the New Outlook forces you to start a whole new blank email whenever you try to switch accounts.

Is there a way you know of to reply or forward to emails from different accounts?