Useful addon ... Rated 5 out of 5 stars
It is very useful to have maximum view of message body but a little difficulty to identify TO and CC mail ids in two line view. I suggest (or request) to highlight TO mail ids (in bold or some other color) to differentiate between CC mail ids.
In the two line header mode the CC addresses are displayed italic and the BCC addresses italic and underlined.
I didn't want to use bold or a different color because then the CC/BCC addresses would appear too important.