Comment 195 for bug 1084

(In reply to comment #50)
> One fix would be to set the "maxheight" attribute of the "msgHeaderView" hbox
> to
> 100 (or 33% or whatever), and its "style" property to "overflow:auto". That
> automatically adds scroll bars to it when the content is larger.
> BUT there is a big problem: Due to rendering issues (?), the whole box gets
> distorted and black when scrolling, and even when pressing the "-" to hide the
> headers. So this isn't a real fix (but were, if everything worked).
>
Using expandedHeaderView instead of msgHeaderView seems to fix the rendering issues when scrolling. For example:
/* Header Scroll userChrome.css Hack */
#expandedHeaderView {
  max-height: 20em !important;
  overflow: auto !important;
}