Expanded columns in folders pane - Thunderbird

From MozillaZine Knowledge Base

You can add columns to the folder pane to display the number of unread messages, the total number of messages, and/or the size of the mail folder. Displaying the number of unread messages is a useful way to avoid having to select a folder to see if it has unread mail.

Thunderbird 3 and newer:

  • Click on the column chooser control and select Unread, Total, and/or Size.

Thunderbird 2 and earlier versions:

  • Check the box for "Show expanded columns in the folder pane" in "Tools -> Options -> Advanced -> General Settings", and then press the "OK" button. This will add a small square control at the right end of the column headers in the folder pane.
  • Click on that control and select Unread, Total, and/or Size.