Once thing that I’ve missed since switching from Apple’s Mail to Mozilla’s Thunderbird, is the way that Mail includes the time and date that the message being replied to was received. Thunderbird does not do this by default, but it’s to make it.

  1. Go to the Preferences window.
    • In Linux: Edit -> Preferences
    • In Windows: Tools -> Options
    • In Mac OS X: Thunderbird -> Preferences
  2. Click on the Advanced button.
  3. Thunderbird Advanced Preferences

  4. Click on the Config Editor… button.
  5. Thunderbird Config Editor

  6. Type mailnews.reply_header_type into the Filter: box.
  7. Double-click on mailnews.reply_header_type, enter the number 3 as the new value, and click OK.