Message tabs enable messages, folders, search results and even some web content to be displayed in tabs within a single Thunderbird window. Similar to Firefox's tabbed browsing, multiple messages can be displayed without opening multiple Thunderbird message windows.
The message tab behavior depends on a preference setting. Thunderbird gives you the option to make messages open in new tabs, new windows or an existing Thunderbird window. You can change this preference in the OptionsPreferences window:
By default, when Thunderbird is opened it creates a single tab. This displays all of the mail accounts and folders in a panel on the left, and a message list and selected message on the right. (The messages displayed depend on which folder and message is selected.)
When you double-click a message, press Enter when a message is highlighted, or right-click a message in the message list and select Open Message in New Tab, the message will be displayed in a new tab:
To open a folder in a tab in the background (that is, to keep focus on the current tab while opening a new tab that contains the selected item), right-click the folder and select Open in New Tab. You can also middle-click a message or folder to open it in a tab in the background.
When you perform a search, the results are displayed in a tab:
When you double-click a newsgroup message or a blog post in the message list, the message or post is displayed in a new tab:
Use the Ctrl + Tab (and Ctrl + Shift + Tab) keystrokes to move to the right or left tab respectively. To move to a specific tab, use Ctrl + <number>, where "<number>" is a digit that represents the desired tab's position from left to right. (For example, to jump to the fourth tab from the left, use Ctrl + 4.)
You can reposition tabs by clicking and dragging individual tabs into the desired position.
Certain kinds of web content can also be displayed in a tab in Thunderbird. For example, if you click Help and select What's New, Thunderbird opens a tab and displays content from the web. However, as a user, you can't select web content to display in a tab - it only happens when the function is invoked from within the Thunderbird program or from within a Thunderbird extension.
To close a tab, either click the close symbol or use the Ctrl + W keyboard shortcut.