Comment 219 for bug 1084

Created an attachment (id=223346)
Screenshot of CSS from comment 92, in TB 1.5

I haven't been able to reproduce the "horizontal lines" problem with any build.

Applying that styling to #expandedHeaderView works better than using
#msgHeaderView, for 2a1/3a1 nightlies. For 1.5, what I'm seeing is much worse
-- the envelope panel is drawn as tall as needed for *all* the headers, but the #msgHeaderView element is given the expected height and a scrollbar, resulting in a large, blank area of the envelope between the scrollbar and the message body (this is seen in the attached screenshot).

In fact, the 2a1/3a1 builds behave better even if using #msgHeaderView.
See bug 240313 comment 12.