The whole new format is the pits! Why on earth do I want an email I open to spread allllllllll the way across the page so I can't read multiple emails at once? Where the **** (if you are going to set my temper off, deal with it) is the "revert to old version" button?
If you’d like to open an email in a new window or as a pop-up, please go to Options-Mail Settings-General-Reading and then check the option you prefer. Then scroll down and save settings.