If you are still engaged and love with your old Gmail interface, then it’s time to say a final good bye as Google to kill old compose interface completely and will roll out pop-up design for everyone. Google a few weeks ago only has added a full-screen option to the new compose with bringing drafts as a minimizable window so that one can write multiple drafts all at once.
The new compose means one can also keep an eye on incoming emails, add support for inline images. If in case, you prefer a full-screen compose experience, just click on the expand button in the top right of the new compose window to switch to full-screen and then all you have to do is to set it as the default by selecting Default to full-screen in the more options menu in the bottom right and you are done.
