Mozilla Thunderbird - Disable Tabs Feature
From ASU HOWTO
Revision as of 17:15, 20 December 2012 by Crwright
Mozilla Thunderbird - Disable Tabs
This setting will prevent the opening of messages in a new tab. They will open in a new window instead.
Go to Tools > Options > Advanced > Reading & Display.
Change "open messages in:" to "a new message window"