You can hold shift while you click on "Compose" or "Reply" to open it in a new window (if that's what you meant).

shift + r

Alas, you'd then still need to click the formatting and header to make the changes you're talking about.

@fuzzwah

I meant as you are replying inline. e.g. http://www.taigeair.com/wp-content/uploads/2013/05/Edit-Subj...

I tried hitting shift+r but it just looks like inline reply in a new window.

Obviously I use email a lot and care a lot about gmail.