New Tab Button 0.1.17

A new option is added to New Tab Button 0.1.17: "Hide tab bar when only one tab is opened". It just sets up mail.tabs.autoHide preference, which is Thunderbird3's hidden option.

By the way, I've been asked about auto update of the addon many times. You cannot receive update notification since it is an experimental addon at AMO. And I don't plan to make it public until Thunderbird3 is released. So, please check this blog or AMO regularly.