Created attachment 8514 [details]
screenshot

I would add help button... OTherwise, it seems like a substatial
improvement.

Yes, a help button would be good. 

There's a general issue of how much Balsa should protect the user
against him/herself. The version shown is at one extreme, with no
protection. Other possibilities:

1. The entry fields and checkbuttons could be initially insensitive,
with an `Edit' toggle button to make them editable.

2. There could be an `Undo' button to revert changes made to the
current identity.

...

n+1. At the other extreme, we could defer changes as long as possible,
and then prompt for confirmation; that's presumably what we're trying
to get away from!

Comments?

The follow-up patch has been commited, closing the report.

BTW, balsa-1.3.7 (prerelease of 1.4.0) is available for download:
http://balsa.gnome.org/