When you have an email message open and an email address is displayed if you
right mouse click over the email address it gives you a right mouse menu where
you can copy and paste the address and do a few other things.

Requesting this same right mouse menu from the preview pane under Contacts. 
It's a hyperlink and if you click on it it will open a message to that person,
but the right mouse click would add a bit of polish.  Sometimes you can to copy
and paste that address into another product.  Thanks

Other information: