Apple Mail disabled the amazing “Letterbox” plugin after the recent Mac OS10.6.8 update. Here’s a link to an easy fix.
Letterbox is a plugin for Apple’s Mail.app that takes advantage of the full width of your monitor. It rearranges the interface into three vertical columns so the message pane is to the right of the message list, rather than below.
MailPluginFix is a free tool which will fix any incompatible Mail.app plugin after an update of Mac OS X.
