This extension reverts a change in the MailNews UI introduced in recent trunk builds.
How I tested:
1. Downloaded and installed a SuiteRunner build 2007080603 (You'll need a build as recent as this or later).
2. Start a MailNews (Messenger) window. Notice that in this build that in the folder pane the behaviour has changed to highlight the whole row and not just the text of the folder label.
2. Installed this extension and restarted.
3. Opened a mailnews (messenger) window and tried to highlight any folder in the folder pane. Notice that the behaviour has reverted to before some brain damaged developer checked in the latest patches.
Conclusion: This extension works as expected and will be welcomed by all trunk testers who prefer the previous behaviour.