Mobile: Long press address to drag and drop between recipient fields.
I was replying to an email with two CC recipients but didn't want to include original sender. Hit reply, deleted the original sender from To: field, but couldn't send my note to the CC: recipients until I moved one to the To: field. I tried long pressing on one address to drag it into the To: field, but no luck. Long pressing and dragging between fields would be a nice efficiency upgrade (rather deleting address from one field and retyping the email address in a different field).
Planned