Comment 101 for bug 1084

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).