Would really love a pop-out window option for compose. If it’s there, I don’t see it. This is very helpful when one needs to reference/search other emails, etc…
Two ways to do this (I suggest you implement both):
Add a little “pop-out” icon in the compose window if you’ve already started writing, to force a new window to open with the compose screen.
Add a “shift-click” option when clicking on the “Compose” button the first time to force a new window from the beginning.
I too second this feature. It is there on the old interface and it comes in handy. Maybe it is not for everyone, but as storyboard mentioned, perhaps add it as a custom feature for those who prefer it. i would add one other possibility to what was requested. A “remember” feature. So that if i select it once it will remember for future messages, so i would not have to force it to pop-out every time. Or have a setting in preferences to allow pop out composing/replying/forwarding by default.