>I do not understand the thought or the need of having the message area width not being the same width of the upper area, seems like a waste of space to me, unless I set the width of the message area larger than the width of the upper area to get horizontal scrollbars (which it does not seem to be the case?), but in that case why don't you use something like width = max(user selected width, upper area width)?

Because it doesn't make sense to have a message width window to be something like 1400 pixels wide. This would make the text extremely difficult to read. This is based on the user's choice. This is why the setting is there.