Thanks. I tried it out. It is not present in the message window, it is outside in the main messages list. It copies/pastes the entire message in source code. There is no facility to highlight individual text in the message window and copy/paste it. Thunderbird can do that too, for eg. Here is a copy/paste of only your text selected from your reply.....
I am on Evolution 2.0.1 and it is working for me. I can do a CTRL+C (or Edit -> Copy), and paste it anywhere I want. /*I can copy only a few lines from the message or the entire message as per my choice.*/
Amish.