Gmail's new default behavior is to pop-up a sub-window when I press "Compose"—not a new window managed by my desktop window manager (WM), but a new HTML-based "window," like for chat. I consider this (typical of Gmail) to be an extremely good interface design decision. This allows me to browse other emails and chat easy as I reply, without having to fuss with my desktop window manager.
I like this behavior so much that when I hit "Reply" to an email, I wish I had the option of popping it out to this Gmail-managed window. Being able to pop it out into a WM-managed window is a nice option if I'm wanting to reference other tabs in my browser, but if I am working primarily in Gmail, it is would be nice to be able to have the option of positioning the reply as if it was a new compose "window".
Is this possible? Am I missing some button or shortcut to accomplish this? Or is this something which has not been implemented in Gmail?
Best Answer
You can do this if you click on the arrow at the top of the reply and select "Pop out reply"
This should open your reply into the sub-window-format compose.
Edit @justingordon asked about a keyboard shortcut for this behavior. Updating the answer.
Holding Shift+ R or A will reply (or replay-all, respectively) in a pop-out window.