Rated 5 out of 5 stars

Great addon, that allows you to hide or show the tab bar whether there are multiple tabs open or not.

This is great as tabs reveal a lot of private information, and if someone is walking past, a simple (customizable) keyboard shortcut can hide the entire tab bar hiding the private information and making it appear that the window has only one page open. Also, works with Firefox 3 if you override the version compatibility with MR Tech's Toolkit.